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Sample records for improved perfectly matched

  1. Efficiency improved scalar wave low-rank extrapolation with an effective perfectly matched layer

    NASA Astrophysics Data System (ADS)

    Chen, Hanming; Zhou, Hui; Xia, Muming

    2017-02-01

    Low-rank extrapolation is a relatively new method for seismic wave simulation. However, the low-rank method involved requires several fast Fourier transforms (FFTs) per time step, and the number of FFTs increases with the time-stepping size and complexity of the model, which leads to high computational cost at each step. To reduce the cost per time step, a more efficient low-rank extrapolation scheme is presented by splitting the original wave propagator into two parts. The first part represents the traditional pseudo-spectral operator, and is calculated by FFT directly. The residual part compensates the time-stepping error, and is approximated by low-rank decomposition. Compared with the conventional low-rank extrapolation scheme, the improved extrapolation scheme enables using a lower rank for the decomposition to attain similar approximation accuracy, which reduces the number of floating-point operations per time step, and thus reduces the total computational cost. To avoid the wraparound effect caused by FFTs, we develop an effective split perfectly matched layer (PML) to absorb outgoing waves near the boundary. Numerical examples verify the accuracy of the developed low-rank extrapolation scheme and the effectiveness of the PML.

  2. Perfecting the Frankenstein Approach: Improved asymptotically matched initial data for non-spinning black hole binaries

    NASA Astrophysics Data System (ADS)

    Yunes, Nicolas; Tichy, Wolfgang

    2006-04-01

    The accuracy of gravitational wave templates produced by numerical simulations is partially determined by the initial data chosen. A promising method to construct accurate data employs asymptotic matching to construct an approximate global 4-metric. In this talk, we will apply this method to a binary system of non-spinning black holes and discuss improvements. A global metric can be constructed by asymptotically matching two tidally perturbed Schwarzschild metrics in isotropic coordinates valid near each hole to an ADMTT post-Newtonian metric valid far from them. As a result, adjacent metrics agree in the matching region up to uncontrolled remainders in the approximations. We build a smooth global 4-metric with transition functions, carefully constructed to avoid introducing errors larger than those in the approximations. The main improvement arises by using metrics in similar coordinates before performing the matching. This similarity leads to adjacent metrics that are similar even near the horizons, thus allowing for a smoother transition and constraint violations. We also construct a map that takes this metric to Kerr-Schild coordinates near each hole.

  3. Perfect and improving

    NASA Astrophysics Data System (ADS)

    Kerr, Robert

    2008-09-01

    As a child I always used to wonder how someone could be described as a "perfect stranger". Not only did I not know any strangers (by definition), I also didn't really see how anyone could be called perfect - that seemed a bridge too far. Nowadays, however, in my early dotage/mid-life crisis/eternally youthful existence (depending on whether you are talking to my friends, family or me) I begin to see that perhaps at last I have achieved a level of perfection not anticipated in my youth. You see, I have almost completely transmogrified myself from a real physics teacher into a pretend sociologist. I am now, and intend to continue to be for some time, a perfect fraud.

  4. An ACCESS Printout on School Based Improvement and Effective Schools: A Perfect Match for Bottom-Up Reform.

    ERIC Educational Resources Information Center

    National Committee for Citizens in Education, Columbia, MD.

    School-based management and improvement, supported by parent and community involvement, offer the most promising route to lasting reform in the public schools. Following an extensive introduction (part I) outlining school-based management and improvement concepts, the effective schools connection, the Dade County (Florida) experience, and 10…

  5. An ACCESS Printout on School Based Improvement and Effective Schools: A Perfect Match for Bottom-Up Reform.

    ERIC Educational Resources Information Center

    National Committee for Citizens in Education, Columbia, MD.

    School-based management and improvement, supported by parent and community involvement, offer the most promising route to lasting reform in the public schools. Following an extensive introduction (part I) outlining school-based management and improvement concepts, the effective schools connection, the Dade County (Florida) experience, and 10…

  6. Cognitive Learning Styles: Can You Engineer a "Perfect" Match?

    ERIC Educational Resources Information Center

    Khuzzan, Sharifah Mazlina Syed; Goulding, Jack Steven

    2016-01-01

    Education and training is widely acknowledged as being one of the key factors for leveraging organisational success. However, it is equally acknowledged that skills development and the acquisition of learning through managed cognitive approaches has yet to provide a "perfect" match. Whilst it is argued that an ideal learning scenario…

  7. An unsplit Convolutional perfectly matched layer technique improved at grazing incidence for the differential anisotropic elastic wave equation: application to 3D heterogeneous near surface slices.

    NASA Astrophysics Data System (ADS)

    Martin, R.; Komatitsch, D.

    2007-05-01

    In geophysical exploration, high computational cost of full waveform inverse problem can be drastically reduced by implementing efficient boundary conditions. In many regions of interest for the oil industry or geophysical exploration, nearly tabular geological structures can be handled and analyzed by setting receivers in wells or/and at large offset. Then, the numerical modelling of waves travelling in thin slices along wells and near surface structures can provide very fast responses if highly accurate absorbing conditions around the slice are introduced in the wave propagation modelling. Here we propose then a Convolutional version of the well known Perfectly Matched layer technique. This optimized version allows the generation of seismic waves travelling close to the boundary layer at almost grazing incidence, which allows the treatment of thin 3D slices. The Perfectly Matched Layer (PML) technique, introduced in 1994 by Bérenger for Maxwell's equations, has become classical in the context of numerical simulations in electromagnetics, in particular for 3D finite difference in the time domain (FDTD) calculations. One of the most attractive properties of a PML model is that no reflection occurs at the interface between the physical domain and the absorbing layer before truncation to a finite-size layer and discretization by a numerical scheme. Therefore, the absorbing layer does not send spurious energy back into the medium. This property holds for any frequency and angle of incidence. However, the layer must be truncated in order to be able to perform numerical simulations, and such truncation creates a reflected wave whose amplitude is amplified by the discretization process. In 2001, Collino and Tsogka introduced a PML model for the elastodynamics equation written as a first-order system in velocity and stress with split unknowns, and discretized it based on the standard 2D staggered-grid finite-difference scheme of Virieux (1986). Then in 2001 and 2004

  8. Perfectly matched layers for Maxwell's equations in second order formulation

    SciTech Connect

    Sjogreen, B; Petersson, A

    2004-07-26

    We consider the two-dimensional Maxwell's equations in domains external to perfectly conducting objects of complex shape. The equations are discretized using a node-centered finite-difference scheme on a Cartesian grid and the boundary condition are discretized to second order accuracy employing an embedded technique which does not suffer from a ''small-cell'' time-step restriction in the explicit time-integration method. The computational domain is truncated by a perfectly matched layer (PML). We derive estimates for both the error due to reflections at the outer boundary of the PML, and due to discretizing the continuous PML equations. Using these estimates, we show how the parameters of the PML can be chosen to make the discrete solution of the PML equations converge to the solution of Maxwell's equations on the unbounded domain, as the grid size goes to zero. Several numerical examples are given.

  9. Asymmetric perfectly matched layer for the absorption of waves

    SciTech Connect

    Vay, Jean-Luc

    2002-02-10

    The Perfectly Matched Layer (PML) has become a standard for comparison in the techniques that have been developed to close the system of Maxwell equations (more generally wave equations) when simulating an open system. The original Berenger PML formulation relies on a split version of Maxwell equations with numerical electric and magnetic conductivities. They present here an extension of this formulation which introduces counterparts of the electric and magnetic conductivities affecting the term which is spatially differentiated in the equations. they phase velocity along each direction is also multiplied by an additional coefficient. They show that, under certain constraints on the additional numerical coefficients, this ''medium'' does not generate any reflection at any angle and any frequency and is then a Perfectly Matched Layer. Technically it is a super-set of Berenger's PML to which it reduces for a specific set of parameters and like it, it is anisotropic. However, unlike the PML, it introduces some asymmetry in the absorption rate and is therefore labeled an APML for Asymmetric Perfectly Matched Layer. They present here the numerical considerations that have led them to introduce such a medium as well as its theory. Several finite-different numerical implementations are derived (in one, two and three dimensions) and the performance of the APML is contrasted with that of the PML in one and two dimensions. Using plane wave analysis, they show that the APML implementations lead to higher absorption rates than the considered PML implementations. Although they have considered in this paper the finite-different discretization of Maxwell-like equations only, the APML system of equations may be used with other discretization schemes, such as finite-elements, and may be applied to other equations, for applications beyond electromagnetics.

  10. On the perfectly matched layer and the DB boundary condition.

    PubMed

    Tedeschi, Nicola; Frezza, Fabrizio; Sihvola, Ari

    2013-10-01

    In this paper, we consider a particular uniaxial material able to achieve the DB boundary condition. We show how, for particular transverse electromagnetic properties, this material behaves like a perfectly matched layer (PML). Moreover, we find that, with an approximation, the material becomes passive, i.e., loses the active part of the permittivity and of the permeability typical of a PML. In this case, the uniaxial medium becomes realizable as a particular absorbing metamaterial. We present simulations with both guided and free-space waves to show the absorbing behavior of the proposed material.

  11. Improved and perfect actions in discrete gravity

    SciTech Connect

    Bahr, Benjamin; Dittrich, Bianca

    2009-12-15

    We consider the notion of improved and perfect actions within Regge calculus. These actions are constructed in such a way that they - although being defined on a triangulation - reproduce the continuum dynamics exactly, and therefore capture the gauge symmetries of general relativity. We construct the perfect action in three dimensions with a cosmological constant, and in four dimensions for one simplex. We conclude with a discussion about Regge calculus with curved simplices, which arises naturally in this context.

  12. Efficient algorithms for the minimum cost perfect matching problem

    SciTech Connect

    Atamturk, A.; Akgul, M.

    1994-12-31

    We present two efficient forest algorithms for the minimum cost perfect matching problem on general graphs. In the multiple augmentation algorithm, we allow augmenting a set of node-disjoint paths in a single stage and show that scanning and updating operations can be delayed to the first time the augmenting paths intersect. Efficiency of the algorithm increases as the number of augmenting paths found per stage gets larger. In the second algorithm initialization of heaps is performed only at the beginning of the algorithm. With a concept of dating/heap correcting the problem is solved at a single stage. In both of the algorithms, we achieved drastic reductions in the total number of time consuming operations such as scanning, updating dual variables and reduced costs. Detailed computational analysis on randomly generated graphs has shown the proposed algorithms to be several times faster than other algorithms in the literature. Hence, we conjecture that employment of the new algorithms in the solution methods of hard optimization problems would speed them up significantly. The complexity of both of the algorithms are O(n{sup 3}) for dense graphs and O(nmlog n) for sparse graphs using splittable heaps.

  13. AN FDTD ALGORITHM WITH PERFECTLY MATCHED LAYERS FOR CONDUCTIVE MEDIA. (R825225)

    EPA Science Inventory

    We extend Berenger's perfectly matched layers (PML) to conductive media. A finite-difference-time-domain (FDTD) algorithm with PML as an absorbing boundary condition is developed for solutions of Maxwell's equations in inhomogeneous, conductive media. For a perfectly matched laye...

  14. AN FDTD ALGORITHM WITH PERFECTLY MATCHED LAYERS FOR CONDUCTIVE MEDIA. (R825225)

    EPA Science Inventory

    We extend Berenger's perfectly matched layers (PML) to conductive media. A finite-difference-time-domain (FDTD) algorithm with PML as an absorbing boundary condition is developed for solutions of Maxwell's equations in inhomogeneous, conductive media. For a perfectly matched laye...

  15. Development of a Perfectly Matched Layer Technique for a Discontinuous-Galerkin Spectral-Element Method

    NASA Technical Reports Server (NTRS)

    Garai, Anirban; Diosady, Laslo T.; Murman, Scott M.; Madavan, Nateri K.

    2016-01-01

    The perfectly matched layer (PML) technique is developed in the context of a high- order spectral-element Discontinuous-Galerkin (DG) method. The technique is applied to a range of test cases and is shown to be superior compared to other approaches, such as those based on using characteristic boundary conditions and sponge layers, for treating the inflow and outflow boundaries of computational domains. In general, the PML technique improves the quality of the numerical results for simulations of practical flow configurations, but it also exhibits some instabilities for large perturbations. A preliminary analysis that attempts to understand the source of these instabilities is discussed.

  16. The perfect match: Do criminal stereotypes bias forensic evidence analysis?

    PubMed

    Smalarz, Laura; Madon, Stephanie; Yang, Yueran; Guyll, Max; Buck, Sarah

    2016-08-01

    This research provided the first empirical test of the hypothesis that stereotypes bias evaluations of forensic evidence. A pilot study (N = 107) assessed the content and consensus of 20 criminal stereotypes by identifying perpetrator characteristics (e.g., sex, race, age, religion) that are stereotypically associated with specific crimes. In the main experiment (N = 225), participants read a mock police incident report involving either a stereotyped crime (child molestation) or a nonstereotyped crime (identity theft) and judged whether a suspect's fingerprint matched a fingerprint recovered at the crime scene. Accompanying the suspect's fingerprint was personal information about the suspect of the type that is routinely available to fingerprint analysts (e.g., race, sex) and which could activate a stereotype. Participants most often perceived the fingerprints to match when the suspect fit the criminal stereotype, even though the prints did not actually match. Moreover, participants appeared to be unaware of the extent to which a criminal stereotype had biased their evaluations. These findings demonstrate that criminal stereotypes are a potential source of bias in forensic evidence analysis and suggest that suspects who fit criminal stereotypes may be disadvantaged over the course of the criminal justice process. (PsycINFO Database Record

  17. Error Control with Perfectly Matched Layer or Damping Layer Treatments for Computational Aeroacoustics with Jet Flows

    NASA Technical Reports Server (NTRS)

    Goodrich, John W.

    2009-01-01

    In this paper we show by means of numerical experiments that the error introduced in a numerical domain because of a Perfectly Matched Layer or Damping Layer boundary treatment can be controlled. These experimental demonstrations are for acoustic propagation with the Linearized Euler Equations with both uniform and steady jet flows. The propagating signal is driven by a time harmonic pressure source. Combinations of Perfectly Matched and Damping Layers are used with different damping profiles. These layer and profile combinations allow the relative error introduced by a layer to be kept as small as desired, in principle. Tradeoffs between error and cost are explored.

  18. Striving for perfection and falling short: The influence of goals on probability matching.

    PubMed

    Gao, Jie; Corter, James E

    2015-07-01

    Probability matching in sequential prediction tasks is argued to occur because participants implicitly adopt the unrealistic goal of perfect prediction of sequences. Biases in the understanding of randomness then lead them to generate mixed rather than pure sequences of predictions in attempting to achieve this goal. In Study 1, N = 350 participants predicted 100 trials of a binary-outcome event. Two factors were manipulated: probability bias (the outcomes were equiprobable or distributed with a 75%-25% bias), and goal type-namely, whether single-trial predictions or the perfect prediction of four-trial sequences was emphasized and rewarded. As we hypothesized, predicting sequences led to more probability-matching behavior than did predicting single trials, for both the bias and no-bias conditions. In Study 1B, we added a control condition to distinguish the effects of the grouped presentation of trials from the effects of sequence-level perfect-prediction rewards. The results supported goal type rather than presentation format as the cause of the Study 1 differences in matching between the sequence and single-trial conditions. In Study 2, all participants (N = 300) predicted the outcomes for five-trial sequences, but with different goal levels being rewarded: 60%, 80%, or 100% correct predictions. The 100% goal resulted in the most probability matching, as hypothesized. Paradoxically, using the inferior strategy of probability matching may be triggered by adopting an unrealistic perfect-prediction goal.

  19. An Absorbing Boundary Condition for the Lattice Boltzmann Method Based on the Perfectly Matched Layer

    PubMed Central

    Najafi-Yazdi, A.; Mongeau, L.

    2012-01-01

    The Lattice Boltzmann Method (LBM) is a well established computational tool for fluid flow simulations. This method has been recently utilized for low Mach number computational aeroacoustics. Robust and nonreflective boundary conditions, similar to those used in Navier-Stokes solvers, are needed for LBM-based aeroacoustics simulations. The goal of the present study was to develop an absorbing boundary condition based on the perfectly matched layer (PML) concept for LBM. The derivation of formulations for both two and three dimensional problems are presented. The macroscopic behavior of the new formulation is discussed. The new formulation was tested using benchmark acoustic problems. The perfectly matched layer concept appears to be very well suited for LBM, and yielded very low acoustic reflection factor. PMID:23526050

  20. Acoustic reverse time migration and perfectly matched layer in boundary-conforming grids by elliptic method

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Zhou, Hui; Chen, Hanming; Sheng, Shanbo; Yuan, Sanyi

    2015-11-01

    Traditionally, finite difference method is chosen as a fast and accurate solution method for numerical simulation of wave equation. However, finite difference method faces obstacles when surface topography and irregular interfaces exist. Boundary-conforming grids by the elliptic method provide an optimal choice for finite difference wavefield simulation in complicated domains containing not only surface topography but also irregular interfaces. By such grids, the calculations of spatial derivatives are transformed by a chain rule into those in the regular computational space, where traditional finite difference schemes are still applicable. Boundary-conforming grids are superior to other irregular grid methods, such as interpolation method, mapping method and unstructured grids, on the aspects of generality, in accuracy and stability. This paper comprehensively applies the elliptic method and acoustic wave equation simulation, reverse time migration, perfectly matched layers in such boundary-conforming grids. The two-dimensional acoustic wave equation is compactly reformulated in boundary-conforming grids by the elliptic method for forward modeling and reverse time migration, and the symmetric and compact form of perfectly matched layers expressed in curvilinear coordinate system are applied to suppress artificial reflections. A stable and explicit second order accuracy finite difference method is used for discretization. Two models are presented to evaluate the ability of boundary-conforming grids to deal with surface topography and complex interfaces, and to demonstrate the feasibility of wavefield propagation and reverse time migration. Comparisons between the numerical simulations with and without the perfectly matched layers are performed to show the effect of the reformulated perfectly matched layer.

  1. Perfectly matched layer for an elastic parabolic equation model in ocean acoustics

    NASA Astrophysics Data System (ADS)

    Xu, Chuanxiu; Zhang, Haigang; Piao, Shengchun; Yang, Shi'e.; Sun, Sipeng; Tang, Jun

    2017-02-01

    The perfectly matched layer (PML) is an effective technique for truncating unbounded domains with minimal spurious reflections. A fluid parabolic equation (PE) model applying PML technique was previously used to analyze the sound propagation problem in a range-dependent waveguide (Lu and Zhu, 2007). However, Lu and Zhu only considered a standard fluid PE to demonstrate the capability of the PML and did not take improved one-way models into consideration. They applied a [1/1] Padé approximant to the parabolic equation. The higher-order PEs are more accurate than standard ones when a very large angle propagation is considered. As for range-dependent problems, the techniques to handle the vertical interface between adjacent regions are mainly energy conserving and single-scattering. In this paper, the PML technique is generalized to the higher order elastic PE, as is to the higher order fluid PE. The correction of energy conserving is used in range-dependent waveguides. Simulation is made in both acoustic cases and seismo-acoustic cases. Range-independent and range-dependent waveguides are both adopted to test the accuracy and efficiency of this method. The numerical results illustrate that a PML is much more effective than an artificial absorbing layer (ABL) both in acoustic and seismo-acoustic sound propagation modeling.

  2. Seismic wavefield simulation by a modified finite element method with a perfectly matched layer absorbing boundary

    NASA Astrophysics Data System (ADS)

    Meng, Weijuan; Fu, Li-Yun

    2017-08-01

    The finite element method is a very important tool for modeling seismic wave propagation in complex media, but it usually consumes a large amount of memory which significantly decreases computational efficiency when solving large-scale seismic problems. Here, a modified finite element method (MFEM) is proposed to improve efficiency. Triangular elements are employed to mesh the topography and the discontinuous interface more flexibly. In the two-dimensional case, the Jacobian matrix is obtained by using three controlling points instead of all nodes in each element with MFEM, which separates the Jacobian matrix from the stiffness matrix. The kernel matrices of the stiffness matrix rather than the global matrix are stored, and memory requirements are thus reduced significantly. Meanwhile, the element-by-element scheme is adopted to spare large sparse matrices and make the program easily parallelized. A second-order perfectly matched layer (PML) is also implemented to eliminate artificial reflections. Finally, the accuracy and efficiency of our algorithm are validated by numerical tests.

  3. The Analysis and Construction of Perfectly Matched Layers for the Linearized Euler Equations

    NASA Technical Reports Server (NTRS)

    Hesthaven, J. S.

    1997-01-01

    We present a detailed analysis of a recently proposed perfectly matched layer (PML) method for the absorption of acoustic waves. The split set of equations is shown to be only weakly well-posed, and ill-posed under small low order perturbations. This analysis provides the explanation for the stability problems associated with the split field formulation and illustrates why applying a filter has a stabilizing effect. Utilizing recent results obtained within the context of electromagnetics, we develop strongly well-posed absorbing layers for the linearized Euler equations. The schemes are shown to be perfectly absorbing independent of frequency and angle of incidence of the wave in the case of a non-convecting mean flow. In the general case of a convecting mean flow, a number of techniques is combined to obtain a absorbing layers exhibiting PML-like behavior. The efficacy of the proposed absorbing layers is illustrated though computation of benchmark problems in aero-acoustics.

  4. An absorbing boundary formulation for the stratified, linearized, ideal MHD equations based on an unsplit, convolutional perfectly matched layer

    NASA Astrophysics Data System (ADS)

    Hanasoge, S. M.; Komatitsch, D.; Gizon, L.

    2010-11-01

    Perfectly matched layers are a very efficient way to absorb waves on the outer edges of media. We present a stable convolutional unsplit perfectly matched formulation designed for the linearized stratified Euler equations. The technique as applied to the Magneto-hydrodynamic (MHD) equations requires the use of a sponge, which, despite placing the perfectly matched status in question, is still highly efficient at absorbing outgoing waves. We study solutions of the equations in the backdrop of models of linearized wave propagation in the Sun. We test the numerical stability of the schemes by integrating the equations over a large number of wave periods.

  5. Efficiency of perfectly matched layers for seismic wave modeling in second-order viscoelastic equations

    NASA Astrophysics Data System (ADS)

    Ping, Ping; Zhang, Yu; Xu, Yixian; Chu, Risheng

    2016-12-01

    In order to improve the perfectly matched layer (PML) efficiency in viscoelastic media, we first propose a split multi-axial PML (M-PML) and an unsplit convolutional PML (C-PML) in the second-order viscoelastic wave equations with the displacement as the only unknown. The advantage of these formulations is that it is easy and efficient to revise the existing codes of the second-order spectral element method (SEM) or finite-element method (FEM) with absorbing boundaries in a uniform equation, as well as more economical than the auxiliary differential equations PML. Three models which are easily suffered from late time instabilities are considered to validate our approaches. Through comparison the M-PML with C-PML efficiency of absorption and stability for long time simulation, it can be concluded that: (1) for an isotropic viscoelastic medium with high Poisson's ratio, the C-PML will be a sufficient choice for long time simulation because of its weak reflections and superior stability; (2) unlike the M-PML with high-order damping profile, the M-PML with second-order damping profile loses its stability in long time simulation for an isotropic viscoelastic medium; (3) in an anisotropic viscoelastic medium, the C-PML suffers from instabilities, while the M-PML with second-order damping profile can be a better choice for its superior stability and more acceptable weak reflections than the M-PML with high-order damping profile. The comparative analysis of the developed methods offers meaningful significance for long time seismic wave modeling in second-order viscoelastic wave equations.

  6. Stable perfectly matched layers for a cold plasma in a strong background magnetic field

    NASA Astrophysics Data System (ADS)

    Bécache, Eliane; Joly, Patrick; Kachanovska, Maryna

    2017-07-01

    This work addresses the question of the construction of stable perfectly matched layers (PMLs) for a cold plasma in the infinitely large background magnetic field. We demonstrate that the traditional, Bérenger's perfectly matched layers are unstable when applied to this model, due to the presence of the backward propagating waves. To overcome this instability, we use a combination of two techniques presented in the article. First of all, we consider a simplified 2D model, which shares with the 3D case one of the difficulties for the PML treatment, namely, the presence of the backward propagating waves. Based on the fact that for a fixed frequency either forward or backward propagating waves are present, we stabilize the PMLs with the help of a frequency-dependent correction. An extra difficulty of the 3D model compared to the 2D case is the presence of both forward and backward waves for a fixed frequency. To overcome this problem we construct a system of equations that consists of two independent systems, which are equivalent to the original model. The first of the systems behaves like the 2D plasma model, and hence the PMLs are stabilized again with the help of the frequency-dependent correction. The second system resembles the Maxwell equations in vacuum, and hence the standard Bérenger's PMLs are stable for it. The systems are solved inside the perfectly matched layer, and coupled to the original Maxwell equations, which are solved in a physical domain, on a discrete level through an artificial layer. The numerical experiments confirm the stability of the new technique.

  7. Sensitive Radio-Frequency Measurements of a Quantum Dot by Tuning to Perfect Impedance Matching

    NASA Astrophysics Data System (ADS)

    Ares, N.; Schupp, F. J.; Mavalankar, A.; Rogers, G.; Griffiths, J.; Jones, G. A. C.; Farrer, I.; Ritchie, D. A.; Smith, C. G.; Cottet, A.; Briggs, G. A. D.; Laird, E. A.

    2016-03-01

    Electrical readout of spin qubits requires fast and sensitive measurements, which are hindered by poor impedance matching to the device. We demonstrate perfect impedance matching in a radio-frequency readout circuit, using voltage-tunable varactors to cancel out parasitic capacitances. An optimized capacitance sensitivity of 1.6 aF /√{Hz } is achieved at a maximum source-drain bias of 170 -μ V root-mean-square and with a bandwidth of 18 MHz. Coulomb blockade in a quantum-dot is measured in both conductance and capacitance, and the two contributions are found to be proportional as expected from a quasistatic tunneling model. We benchmark our results against the requirements for single-shot qubit readout using quantum capacitance, a goal that has so far been elusive.

  8. On absorbing boundary conditions for linearized Euler equations by a perfectly matched layer

    NASA Technical Reports Server (NTRS)

    Hu, Fang Q.

    1995-01-01

    Recently, Berenger introduced a Perfectly Matched Layer (PML) technique for absorbing electromagnetic waves. In the present paper, a perfectly matched layer is proposed for absorbing out-going two-dimensional waves in a uniform mean flow, generated by linearized Euler equations. It is well known that the linearized Euler equations support acoustic waves, which travel with the speed of sound relative to the mean flow, and vorticity and entropy waves, which travel with the mean flow. The PML equations to be used at a region adjacent to the artificial boundary for absorbing these linear waves are defined. Plane waves solutions to the PML equations are developed and wave propagation and absorption properties are given. It is shown that the theoretical reflection coefficients at an interface between the Euler and PML domains are zero, independent of the angle of incidence and frequency of the waves. As such, the present study points out a possible alternative approach for absorbing out-going waves of the Euler equations with little or no reflection in computation. Numerical examples that demonstrate the validity of the proposed PML equations are also presented.

  9. Effect of perfectly matched layer reflection coefficient on modal analysis of leaky waveguide modes.

    PubMed

    Lai, Chih-Hsien; Chang, Hung-chun

    2011-01-17

    The reflection coefficient is one important parameter of the perfectly matched layer (PML). Here we investigate its effect on the modal analysis of leaky waveguide modes by examining three different leaky waveguide structures, i.e., the holey fiber, the air-core terahertz pipe waveguide, and the gain-guided and index-antiguided slab waveguide. Numerical results reveal that the typical values 10(-8) ~10(-12) are inadequate for obtaining the imaginary part of the complex propagation constant, and the suggested reflection coefficient would be much smaller, for example, 10(-50) or 10(-100). With such a small coefficient, both the computational window size and the PML thickness can be significantly reduced without loss of stability. Moreover, in some cases, the modal field profiles can only be accurately obtained with such a small coefficient.

  10. Perfectly matched layer absorbing boundary condition for nonlinear two-fluid plasma equations

    NASA Astrophysics Data System (ADS)

    Sun, X. F.; Jiang, Z. H.; Hu, X. W.; Zhuang, G.; Jiang, J. F.; Guo, W. X.

    2015-04-01

    Numerical instability occurs when coupled Maxwell equations and nonlinear two-fluid plasma equations are solved using finite difference method through parallel algorithm. Thus, a perfectly matched layer (PML) boundary condition is set to avoid the instability caused by velocity and density gradients between vacuum and plasma. A splitting method is used to first decompose governing equations to time-dependent nonlinear and linear equations. Then, a proper complex variable is used for the spatial derivative terms of the time-dependent nonlinear equation. Finally, with several auxiliary function equations, the governing equations of the absorbing boundary condition are derived by rewriting the frequency domain PML in the original physical space and time coordinates. Numerical examples in one- and two-dimensional domains show that the PML boundary condition is valid and effective. PML stability depends on the absorbing coefficient and thickness of absorbing layers.

  11. Unsplit complex frequency shifted perfectly matched layer for second-order wave equation using auxiliary differential equations.

    PubMed

    Gao, Yingjie; Zhang, Jinhai; Yao, Zhenxing

    2015-12-01

    The complex frequency shifted perfectly matched layer (CFS-PML) can improve the absorbing performance of PML for nearly grazing incident waves. However, traditional PML and CFS-PML are based on first-order wave equations; thus, they are not suitable for second-order wave equation. In this paper, an implementation of CFS-PML for second-order wave equation is presented using auxiliary differential equations. This method is free of both convolution calculations and third-order temporal derivatives. As an unsplit CFS-PML, it can reduce the nearly grazing incidence. Numerical experiments show that it has better absorption than typical PML implementations based on second-order wave equation.

  12. A novel unsplit perfectly matched layer for the second-order acoustic wave equation.

    PubMed

    Ma, Youneng; Yu, Jinhua; Wang, Yuanyuan

    2014-08-01

    When solving acoustic field equations by using numerical approximation technique, absorbing boundary conditions (ABCs) are widely used to truncate the simulation to a finite space. The perfectly matched layer (PML) technique has exhibited excellent absorbing efficiency as an ABC for the acoustic wave equation formulated as a first-order system. However, as the PML was originally designed for the first-order equation system, it cannot be applied to the second-order equation system directly. In this article, we aim to extend the unsplit PML to the second-order equation system. We developed an efficient unsplit implementation of PML for the second-order acoustic wave equation based on an auxiliary-differential-equation (ADE) scheme. The proposed method can benefit to the use of PML in simulations based on second-order equations. Compared with the existing PMLs, it has simpler implementation and requires less extra storage. Numerical results from finite-difference time-domain models are provided to illustrate the validity of the approach.

  13. Perfectly matched layers in a divergence preserving ADI scheme for electromagnetics

    SciTech Connect

    Kraus, C.; Adelmann, A.

    2012-01-01

    For numerical simulations of highly relativistic and transversely accelerated charged particles including radiation fast algorithms are needed. While the radiation in particle accelerators has wavelengths in the order of 100 {mu}m the computational domain has dimensions roughly five orders of magnitude larger resulting in very large mesh sizes. The particles are confined to a small area of this domain only. To resolve the smallest scales close to the particles subgrids are envisioned. For reasons of stability the alternating direction implicit (ADI) scheme by Smithe et al. [D.N. Smithe, J.R. Cary, J.A. Carlsson, Divergence preservation in the ADI algorithms for electromagnetics, J. Comput. Phys. 228 (2009) 7289-7299] for Maxwell equations has been adopted. At the boundary of the domain absorbing boundary conditions have to be employed to prevent reflection of the radiation. In this paper we show how the divergence preserving ADI scheme has to be formulated in perfectly matched layers (PML) and compare the performance in several scenarios.

  14. Perfectly Matched Layers versus discrete transparent boundary conditions in quantum device simulations

    SciTech Connect

    Mennemann, Jan-Frederik Jüngel, Ansgar

    2014-10-15

    Discrete transparent boundary conditions (DTBC) and the Perfectly Matched Layers (PML) method for the realization of open boundary conditions in quantum device simulations are compared, based on the stationary and time-dependent Schrödinger equation. The comparison includes scattering state, wave packet, and transient scattering state simulations in one and two space dimensions. The Schrödinger equation is discretized by a second-order Crank–Nicolson method in case of DTBC. For the discretization with PML, symmetric second-, fourth-, and sixth-order spatial approximations as well as Crank–Nicolson and classical Runge–Kutta time-integration methods are employed. In two space dimensions, a ring-shaped quantum waveguide device is simulated in the stationary and transient regime. As an application, a simulation of the Aharonov–Bohm effect in this device is performed, showing the excitation of bound states localized in the ring region. The numerical experiments show that the results obtained from PML are comparable to those obtained using DTBC, while keeping the high numerical efficiency and flexibility as well as the ease of implementation of the former method. -- Highlights: •In-depth comparison between discrete transparent boundary conditions (DTBC) and PML. •First 2-D transient scattering state simulations using DTBC. •First 2-D transient scattering state simulations of the Aharonov–Bohm effect.

  15. Perfectly Matched Layer for Linearized Euler Equations in Open and Ducted Domains

    NASA Technical Reports Server (NTRS)

    Tam, Christopher K. W.; Auriault, Laurent; Cambuli, Francesco

    1998-01-01

    Recently, perfectly matched layer (PML) as an absorbing boundary condition has widespread applications. The idea was first introduced by Berenger for electromagnetic waves computations. In this paper, it is shown that the PML equations for the linearized Euler equations support unstable solutions when the mean flow has a component normal to the layer. To suppress such unstable solutions so as to render the PML concept useful for this class of problems, it is proposed that artificial selective damping terms be added to the discretized PML equations. It is demonstrated that with a proper choice of artificial mesh Reynolds number, the PML equations can be made stable. Numerical examples are provided to illustrate that the stabilized PML performs well as an absorbing boundary condition. In a ducted environment, the wave mode are dispersive. It will be shown that the group velocity and phase velocity of these modes can have opposite signs. This results in a confined environment, PML may not be suitable as an absorbing boundary condition.

  16. Crosswell electromagnetic modeling from impulsive source: Optimization strategy for dispersion suppression in convolutional perfectly matched layer

    PubMed Central

    Fang, Sinan; Pan, Heping; Du, Ting; Konaté, Ahmed Amara; Deng, Chengxiang; Qin, Zhen; Guo, Bo; Peng, Ling; Ma, Huolin; Li, Gang; Zhou, Feng

    2016-01-01

    This study applied the finite-difference time-domain (FDTD) method to forward modeling of the low-frequency crosswell electromagnetic (EM) method. Specifically, we implemented impulse sources and convolutional perfectly matched layer (CPML). In the process to strengthen CPML, we observed that some dispersion was induced by the real stretch κ, together with an angular variation of the phase velocity of the transverse electric plane wave; the conclusion was that this dispersion was positively related to the real stretch and was little affected by grid interval. To suppress the dispersion in the CPML, we first derived the analytical solution for the radiation field of the magneto-dipole impulse source in the time domain. Then, a numerical simulation of CPML absorption with high-frequency pulses qualitatively amplified the dispersion laws through wave field snapshots. A numerical simulation using low-frequency pulses suggested an optimal parameter strategy for CPML from the established criteria. Based on its physical nature, the CPML method of simply warping space-time was predicted to be a promising approach to achieve ideal absorption, although it was still difficult to entirely remove the dispersion. PMID:27585538

  17. Unified perfectly matched layer for finite-difference time-domain modeling of dispersive optical materials.

    PubMed

    Udagedara, Indika; Premaratne, Malin; Rukhlenko, Ivan D; Hattori, Haroldo T; Agrawal, Govind P

    2009-11-09

    Finite-difference time-domain (FDTD) simulations of any electromagnetic problem require truncation of an often-unbounded physical region by an electromagnetically bounded region by deploying an artificial construct known as the perfectly matched layer (PML). As it is not possible to construct a universal PML that is non-reflective for different materials, PMLs that are tailored to a specific problem are required. For example, depending on the number of dispersive materials being truncated at the boundaries of a simulation region, an FDTD code may contain multiple sets of update equations for PML implementations. However, such an approach is prone to introducing coding errors. It also makes it extremely difficult to maintain and upgrade an existing FDTD code. In this paper, we solve this problem by developing a new, unified PML algorithm that can effectively truncate all types of linearly dispersive materials. The unification of the algorithm is achieved by employing a general form of the medium permittivity that includes three types of dielectric response functions, known as the Debye, Lorentz, and Drude response functions, as particular cases. We demonstrate the versatility and flexibility of the new formulation by implementing a single FDTD code to simulate absorption of electromagnetic pulse inside a medium that is adjacent to dispersive materials described by different dispersion models. The proposed algorithm can also be used for simulations of optical phenomena in metamaterials and materials exhibiting negative refractive indices.

  18. Crosswell electromagnetic modeling from impulsive source: Optimization strategy for dispersion suppression in convolutional perfectly matched layer

    NASA Astrophysics Data System (ADS)

    Fang, Sinan; Pan, Heping; Du, Ting; Konaté, Ahmed Amara; Deng, Chengxiang; Qin, Zhen; Guo, Bo; Peng, Ling; Ma, Huolin; Li, Gang; Zhou, Feng

    2016-09-01

    This study applied the finite-difference time-domain (FDTD) method to forward modeling of the low-frequency crosswell electromagnetic (EM) method. Specifically, we implemented impulse sources and convolutional perfectly matched layer (CPML). In the process to strengthen CPML, we observed that some dispersion was induced by the real stretch κ, together with an angular variation of the phase velocity of the transverse electric plane wave; the conclusion was that this dispersion was positively related to the real stretch and was little affected by grid interval. To suppress the dispersion in the CPML, we first derived the analytical solution for the radiation field of the magneto-dipole impulse source in the time domain. Then, a numerical simulation of CPML absorption with high-frequency pulses qualitatively amplified the dispersion laws through wave field snapshots. A numerical simulation using low-frequency pulses suggested an optimal parameter strategy for CPML from the established criteria. Based on its physical nature, the CPML method of simply warping space-time was predicted to be a promising approach to achieve ideal absorption, although it was still difficult to entirely remove the dispersion.

  19. Near-field performance analysis of locally-conformal perfectly matched absorbers via Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Ozgun, Ozlem; Kuzuoglu, Mustafa

    2007-12-01

    In the numerical solution of some boundary value problems by the finite element method (FEM), the unbounded domain must be truncated by an artificial absorbing boundary or layer to have a bounded computational domain. The perfectly matched layer (PML) approach is based on the truncation of the computational domain by a reflectionless artificial layer which absorbs outgoing waves regardless of their frequency and angle of incidence. In this paper, we present the near-field numerical performance analysis of our new PML approach, which we call as locally-conformal PML, using Monte Carlo simulations. The locally-conformal PML method is an easily implementable conformal PML implementation, to the problem of mesh truncation in the FEM. The most distinguished feature of the method is its simplicity and flexibility to design conformal PMLs over challenging geometries, especially those with curvature discontinuities, in a straightforward way without using artificial absorbers. The method is based on a special complex coordinate transformation which is 'locally-defined' for each point inside the PML region. The method can be implemented in an existing FEM software by just replacing the nodal coordinates inside the PML region by their complex counterparts obtained via complex coordinate transformation. We first introduce the analytical derivation of the locally-conformal PML method for the FEM solution of the two-dimensional scalar Helmholtz equation arising in the mathematical modeling of various steady-state (or, time-harmonic) wave phenomena. Then, we carry out its numerical performance analysis by means of some Monte Carlo simulations which consider both the problem of constructing the two-dimensional Green's function, and some specific cases of electromagnetic scattering.

  20. Impact of Recipient and Donor Obesity Match on the Outcomes of Liver Transplantation: All Matches Are Not Perfect

    PubMed Central

    Tumin, Dmitry; Conteh, Lanla F.; Hanje, A. James; Michaels, Anthony J.; Hayes, Don; Black, Sylvester M.

    2016-01-01

    There is a paucity of literature examining recipient-donor obesity matching on liver transplantation outcomes. The United Network for Organ Sharing database was queried for first-time recipients of liver transplant whose age was ≥18 between January 2003 and September 2013. Outcomes including patient and graft survival at 30 days, 1 year, and 5 years and overall, liver retransplantation, and length of stay were compared between nonobese recipients receiving a graft from nonobese donors and obese recipient-obese donor, obese recipient-nonobese donor, and nonobese recipient-obese donor pairs. 51,556 LT recipients were identified, including 34,217 (66%) nonobese and 17,339 (34%) obese recipients. The proportions of patients receiving an allograft from an obese donor were 24% and 29%, respectively, among nonobese and obese recipients. Graft loss (HR: 1.27; 95% CI: 1.09–1.46; p = 0.002) and mortality (HR: 1.38; 95% CI: 1.16–1.65; p < 0.001) at 30 days were increased in the obese recipient-obese donor pair. However, 1-year graft (HR: 0.83; 95% CI: 0.74–0.93; p = 0.002) and patient (HR: 0.84; 95% CI: 0.74–0.95; p = 0.007) survival and overall patient (HR: 0.93; 95% CI: 0.86–1.00; p = 0.042) survival were favorable. There is evidence of recipient and donor obesity disadvantage early, but survival curves demonstrate improved long-term outcomes. It is important to consider obesity in the donor-recipient match. PMID:27688905

  1. Quantitative angle-resolved small-spot reflectance measurements on plasmonic perfect absorbers: impedance matching and disorder effects.

    PubMed

    Tittl, Andreas; Harats, Moshe G; Walter, Ramon; Yin, Xinghui; Schäferling, Martin; Liu, Na; Rapaport, Ronen; Giessen, Harald

    2014-10-28

    Plasmonic devices with absorbance close to unity have emerged as essential building blocks for a multitude of technological applications ranging from trace gas detection to infrared imaging. A crucial requirement for such elements is the angle independence of the absorptive performance. In this work, we develop theoretically and verify experimentally a quantitative model for the angular behavior of plasmonic perfect absorber structures based on an optical impedance matching picture. To achieve this, we utilize a simple and elegant k-space measurement technique to record quantitative angle-resolved reflectance measurements on various perfect absorber structures. Particularly, this method allows quantitative reflectance measurements on samples where only small areas have been nanostructured, for example, by electron-beam lithography. Combining these results with extensive numerical modeling, we find that matching of both the real and imaginary parts of the optical impedance is crucial to obtain perfect absorption over a large angular range. Furthermore, we successfully apply our model to the angular dispersion of perfect absorber geometries with disordered plasmonic elements as a favorable alternative to current array-based designs.

  2. Application of Convolution Perfectly Matched Layer in MRTD scattering model for non-spherical aerosol particles and its performance analysis

    NASA Astrophysics Data System (ADS)

    Hu, Shuai; Gao, Taichang; Li, Hao; Yang, Bo; Jiang, Zidong; Liu, Lei; Chen, Ming

    2017-10-01

    The performance of absorbing boundary condition (ABC) is an important factor influencing the simulation accuracy of MRTD (Multi-Resolution Time-Domain) scattering model for non-spherical aerosol particles. To this end, the Convolution Perfectly Matched Layer (CPML), an excellent ABC in FDTD scheme, is generalized and applied to the MRTD scattering model developed by our team. In this model, the time domain is discretized by exponential differential scheme, and the discretization of space domain is implemented by Galerkin principle. To evaluate the performance of CPML, its simulation results are compared with those of BPML (Berenger's Perfectly Matched Layer) and ADE-PML (Perfectly Matched Layer with Auxiliary Differential Equation) for spherical and non-spherical particles, and their simulation errors are analyzed as well. The simulation results show that, for scattering phase matrices, the performance of CPML is better than that of BPML; the computational accuracy of CPML is comparable to that of ADE-PML on the whole, but at scattering angles where phase matrix elements fluctuate sharply, the performance of CPML is slightly better than that of ADE-PML. After orientation averaging process, the differences among the results of different ABCs are reduced to some extent. It also can be found that ABCs have a much weaker influence on integral scattering parameters (such as extinction and absorption efficiencies) than scattering phase matrices, this phenomenon can be explained by the error averaging process in the numerical volume integration.

  3. Development of a Perfectly Matched Layer Technique for a Discontinuous-Galerkin Spectral-Element Method

    NASA Technical Reports Server (NTRS)

    Garai, Anirban; Murman, Scott M.; Madavan, Nateri K.

    2016-01-01

    used involves modeling the pressure fluctuations as acoustic waves propagating in the far-field relative to a single noise-source inside the buffer region. This approach treats vorticity-induced pressure fluctuations the same as acoustic waves. Another popular approach, often referred to as the "sponge layer," attempts to dampen the flow perturbations by introducing artificial dissipation in the buffer region. Although the artificial dissipation removes all perturbations inside the sponge layer, incoming waves are still reflected from the interface boundary between the computational domain and the sponge layer. The effect of these refkections can be somewhat mitigated by appropriately selecting the artificial dissipation strength and the extent of the sponge layer. One of the most promising variants on the buffer region approach is the Perfectly Matched Layer (PML) technique. The PML technique mitigates spurious reflections from boundaries and interfaces by dampening the perturbation modes inside the buffer region such that their eigenfunctions remain unchanged. The technique was first developed by Berenger for application to problems involving electromagnetic wave propagation. It was later extended to the linearized Euler, Euler and Navier-Stokes equations by Hu and his coauthors. The PML technique ensures the no-reflection property for all waves, irrespective of incidence angle, wavelength, and propagation direction. Although the technique requires the solution of a set of auxiliary equations, the computational overhead is easily justified since it allows smaller domain sizes and can provide better accuracy, stability, and convergence of the numerical solution. In this paper, the PML technique is developed in the context of a high-order spectral-element Discontinuous Galerkin (DG) method. The technique is compared to other approaches to treating the in flow and out flow boundary, such as those based on using characteristic boundary conditions and sponge layers. The

  4. A perfectly matched layer for fluid-solid problems: Application to ocean-acoustics simulations with solid ocean bottoms.

    PubMed

    Xie, Zhinan; Matzen, René; Cristini, Paul; Komatitsch, Dimitri; Martin, Roland

    2016-07-01

    A time-domain Legendre spectral-element method is described for full-wave simulation of ocean acoustics models, i.e., coupled fluid-solid problems in unbounded or semi-infinite domains, taking into account shear wave propagation in the ocean bottom. The technique can accommodate range-dependent and depth-dependent wave speed and density, as well as steep ocean floor topography. For truncation of the infinite domain, to efficiently absorb outgoing waves, a fluid-solid complex-frequency-shifted unsplit perfectly matched layer is introduced based on the complex coordinate stretching technique. The complex stretching is rigorously taken into account in the derivation of the fluid-solid matching condition inside the absorbing layer, which has never been done before in the time domain. Two implementations are designed: a convolutional formulation and an auxiliary differential equation formulation because the latter allows for implementation of high-order time schemes, leading to reduced numerical dispersion and dissipation, a topic of importance, in particular, in long-range ocean acoustics simulations. The method is validated for a two dimensional fluid-solid Pekeris waveguide and for a three dimensional seamount model, which shows that the technique is accurate and numerically long-time stable. Compared with widely used paraxial absorbing boundary conditions, the perfectly matched layer is significantly more efficient at absorbing both body waves and interface waves.

  5. Perfect match? Generation Y as change agents for information communication technology implementation in healthcare.

    PubMed

    Yee, Kwang Chien; Miils, Erin; Airey, Caroline

    2008-01-01

    The current healthcare delivery model will not meet future healthcare demands. The only sustainable healthcare future is one that best leverages advances in technology to improve productivity and efficiency. Information communication technology (ICT) has, therefore, been touted as the panacea of future healthcare challenges. Many ICT projects in healthcare, however, fail to deliver on their promises to transform the healthcare system. From a technologist's perspective, this is often due to the lack of socio-technical consideration. From a socio-cultural perspective, however, there is often strong inertia to change. While the utilisation of user-centred design principles will generate a new wave of enthusiasm among technologists, this has to be matched with socio-cultural changes within the healthcare system. Generation Y healthcare workers might be the socio-cultural factor required, in combination with new technology, to transform the healthcare system. Generation Y has generated significant technology-driven changes in many other industries. The socio-cultural understanding of generation Y healthcare workers is essential to guide the design and implementation of ICT solutions for a sustainable healthcare future. This paper presents the initial analysis of our qualitative study which aims to generate in-depth conceptual insights of generation Y healthcare workers and their view of ICT in healthcare. Our results show that generation Y healthcare workers might assist future ICT implementation in healthcare. This paper, however, argues that significant changes to the current healthcare organisation will be required in order to unleash the full potential of generation Y workers and ICT implementation. Finally, this paper presents some strategies to empower generation Y workers as change agents for a sustainable future healthcare system.

  6. Improved techniques for lower bounds for odd perfect numbers

    NASA Astrophysics Data System (ADS)

    Brent, R. P.; Cohen, G. L.; Riele, H. J. J. Te

    1991-10-01

    If N is an odd perfect number, and {q^k}\\vert\\vert N , q prime, k even, then it is almost immediate that N > {q^{2k}} . We prove here that, subject to certain conditions verifiable in polynomial time, in fact N > {q^{5k/2}} . Using this and related results, we are able to extend the computations in an earlier paper to show that N > {10^{300}} .

  7. Incident angle insensitive tunable multichannel perfect absorber consisting of nonlinear plasma and matching metamaterials

    SciTech Connect

    Kong, Xiang-kun; Liu, Shao-Bin Bian, Bo-rui; Chen, Chen; Zhang, Hai-feng

    2014-12-15

    A novel, compact, and multichannel nonreciprocal absorber through a wave tunneling mechanism in epsilon-negative and matching metamaterials is theoretically proposed. Nonreciprocal absorption properties are acquired via the coupling together of evanescent and propagating waves in an asymmetric configuration, constituted of nonlinear plasma alternated with matching metamaterial. The absorption channel number can be adjusted by changing the periodic number. Due to the positive feedback between nonlinear permittivity of plasma and the inner electric field, bistable absorption and reflection are achieved. Moreover, compared with some truncated photonic crystal or multilayered designs proposed before, our design is more compact and independent of incident angle or polarization. This kind of multilayer structure offers additional opportunities to design novel omnidirectional electromagnetic wave absorbers.

  8. Matched elastic constants for a perfect helical planar state and a fast switching time in chiral nematic liquid crystals.

    PubMed

    Yu, Meina; Zhou, Xiaochen; Jiang, Jinghua; Yang, Huai; Yang, Deng-Ke

    2016-05-11

    Chiral nematic liquid crystals possess a self-assembled helical structure and exhibit unique selective reflection in visible and infrared light regions. Their optical properties can be electrically tuned. The tuning involves the unwinding and restoring of the helical structure. We carried out an experimental study on the mechanism of the restoration of the helical structure. We constructed chiral nematic liquid crystals with variable elastic constants by doping bent-dimers and studied their impact on the restoration. With matched twist and bend elastic constants, the helical structure can be restored dramatically fast from the field-induced homeotropic state. Furthermore, defects can be eliminated to produce a perfect planar state which exhibits high selective reflection.

  9. Effectiveness of Complex Frequency Shifted Perfectly Matched Layers formulation for acoustic wave propagation in the context of seismic oceanography

    NASA Astrophysics Data System (ADS)

    Kormann, Jean; Sallares, Valenti; Biescas, Berta; Cobo, Pedro

    2010-05-01

    Recent research has shown that multichannel seismic data provide images not only from Solid Earth but also from the oceanic interior. The water reflectivity is produced by faint impedance contrasts between neighbouring water masses showing slightly different temperature and salinity. The horizontal resolution of the seismic profiles is two orders of magnitude better than more usual hydrographic sections based on repeated CTD casts, arousing growing interest for seismic oceanography within the oceanographic community. One of the current research lines is developing tools to extract information of oceanographic interest other than the location of the seismic reflectors, such as sound speed, temperature or salinity, from the seismic data. A potential candidate technique is full waveform inversion. Because reflectivity of water masses can be as low as 10-4, the direct modelling of wave propagation to be incorporated in full waveform inversion schemes requires the total control of the boundary reflections. In this work we show that Complex Frequency Shifted Perfectly Matched Layer (CFS-PML) offers a better alternative to classical Perfectly Matched Layer formulation to fulfill these requirements, and has logically been extended to acoustic equations. A Second-order CFS-PML formulation for acoustic wave equation is presented, such that the boundary reflection may be set to be less than a 10-5 of the incident wave. Additionally, we show that our CFS-PML, combined with a sixth-order spatial discretization of the Laplacian operator, allows to precisely model the extremely weak wavefield scattered by the oceanic finestructure. The effectiveness of the scheme described above is demonstrated by comparison of a modeled and real data. For this purpose we will use an inverted sound speed map derived from a combination of seismic and hydrographic data as entry for our modeling, and then compare the final result with data acquired along a real seismic section. We conclude by

  10. Improving The Perfect Storm: Overcoming Barriers To Climate Literacy

    NASA Astrophysics Data System (ADS)

    Tillinger, D.

    2015-12-01

    Students and scientists are trained to speak different languages. Climate science, and the geosciences more broadly, are strictly classroom topics, not subjects appropriate for casual conversation, social media, or creative projects. When students are aware of climate change through the mainstream media, it is nearly always in a political or technological context rather than a scientific one. However, given the opportunity, students are perfectly capable of not only understanding the science behind climate change, but communicating it to their peers. At the American Museum of Natural History, a group of underprivileged high school students visited Nature's Fury: The Science of Natural Disasters to learn about volcanoes, earthquakes, and climate change impacts. They were then able to write pitches and develop trailers for scientifically accurate, but still compelling, disaster movies. Arts in Parts, a creative outreach group formed as a response to Hurricane Sandy, facilitated a workshop in which younger children made mobiles from beach debris they collected while learning about the the threat of sea level rise locally and globally. Participants in an undergraduate natural disasters class wrote guides to understanding climate change that remained factual while showing great creativity and reflecting the personality of each student. Art, humor, and popular culture are the languages that society chooses to use; scientific literacy might benefit from their inclusion.

  11. Improving the Nephrology Match: the Path Forward.

    PubMed

    Hsu, Chi-yuan; Parker, Mark G; Ross, Michael J; Schmidt, Rebecca J; Harris, Raymond C

    2015-11-01

    The Fellowship Match process was designed to provide applicants and program directors with an opportunity to consider all their options before making decisions about post-residency training. In a Match, applicants can choose the programs that best suit their career goals, and program directors can consider all candidates before preparing a rank order list. The Match is a contract, requiring obligations of both programs and applicants to achieve success, ensure uniformity, and standardize participation.

  12. Perfect Match. PEN.

    ERIC Educational Resources Information Center

    Clements, Rebecca

    A teacher had always allowed 20 minutes for silent reading in her classroom. But when she looked at her Year 3/4 composite class, she noticed that although some students were reading, some were not. She decided to explore why they might not be reading. She focused on three students--a boy with severe learning difficulties and an auditory…

  13. A framework for solving atomistic phonon-structure scattering problems in the frequency domain using perfectly matched layer boundaries

    SciTech Connect

    Kakodkar, Rohit R.; Feser, Joseph P.

    2015-09-07

    We present a numerical approach to the solution of elastic phonon-interface and phonon-nanostructure scattering problems based on a frequency-domain decomposition of the atomistic equations of motion and the use of perfectly matched layer (PML) boundaries. Unlike molecular dynamic wavepacket analysis, the current approach provides the ability to simulate scattering from individual phonon modes, including wavevectors in highly dispersive regimes. Like the atomistic Green's function method, the technique reduces scattering problems to a system of linear algebraic equations via a sparse, tightly banded matrix regardless of dimensionality. However, the use of PML boundaries enables rapid absorption of scattered wave energies at the boundaries and provides a simple and inexpensive interpretation of the scattered phonon energy flux calculated from the energy dissipation rate in the PML. The accuracy of the method is demonstrated on connected monoatomic chains, for which an analytic solution is known. The parameters defining the PML are found to affect the performance and guidelines for selecting optimal parameters are given. The method is used to study the energy transmission coefficient for connected diatomic chains over all available wavevectors for both optical and longitudinal phonons; it is found that when there is discontinuity between sublattices, even connected chains of equivalent acoustic impedance have near-zero transmission coefficient for short wavelengths. The phonon scattering cross section of an embedded nanocylinder is calculated in 2D for a wide range of frequencies to demonstrate the extension of the method to high dimensions. The calculations match continuum theory for long-wavelength phonons and large cylinder radii, but otherwise show complex physics associated with discreteness of the lattice. Examples include Mie oscillations which terminate when incident phonon frequencies exceed the maximum available frequency in the embedded nanocylinder, and

  14. Application of the perfectly matched layer in 2.5D marine controlled-source electromagnetic modeling

    NASA Astrophysics Data System (ADS)

    Li, Gang; Han, Bo

    2017-09-01

    For the traditional framework of EM modeling algorithms, the Dirichlet boundary is usually used which assumes the field values are zero at the boundaries. This crude condition requires that the boundaries should be sufficiently far away from the area of interest. Although cell sizes could become larger toward the boundaries as electromagnetic wave is propagated diffusively, a large modeling area may still be necessary to mitigate the boundary artifacts. In this paper, the complex frequency-shifted perfectly matched layer (CFS-PML) in stretching Cartesian coordinates is successfully applied to 2.5D frequency-domain marine controlled-source electromagnetic (CSEM) field modeling. By using this PML boundary, one can restrict the modeling area of interest to the target region. Only a few absorbing layers surrounding the computational area can effectively depress the artificial boundary effect without losing the numerical accuracy. A 2.5D marine CSEM modeling scheme with the CFS-PML is developed by using the staggered finite-difference discretization. This modeling algorithm using the CFS-PML is of high accuracy, and shows advantages in computational time and memory saving than that using the Dirichlet boundary. For 3D problem, this computation time and memory saving should be more significant.

  15. On the use of Perfectly Matched Layers at corners for scattering problems with sign-changing coefficients

    NASA Astrophysics Data System (ADS)

    Bonnet-Ben Dhia, A.-S.; Carvalho, C.; Chesnel, L.; Ciarlet, P.

    2016-10-01

    We investigate in a 2D setting the scattering of time-harmonic electromagnetic waves by a plasmonic device, represented as a non-dissipative bounded and penetrable obstacle with a negative permittivity. Using the T-coercivity approach, we first prove that the problem is well-posed in the classical framework Hloc1 if the negative permittivity does not lie in some critical interval whose definition depends on the shape of the device. When the latter has corners, for values inside the critical interval, unusual strong singularities for the electromagnetic field can appear. In that case, well-posedness is obtained by imposing a radiation condition at the corners to select the outgoing black-hole plasmonic wave, that is the one which carries energy towards the corners. A simple and systematic criterion is given to define what is the outgoing solution. Finally, we propose an original numerical method based on the use of Perfectly Matched Layers at the corners. We emphasize that it is necessary to design an ad hoc technique because the field is too singular to be captured with standard finite element methods.

  16. Perfectly matched layer stability in 3-D finite-difference time-domain simulation of electroacoustic wave propagation in piezoelectric crystals with different symmetry class.

    PubMed

    Nova, Omar; Peña, Néstor; Ney, Michel

    2015-03-01

    Perfectly matched layer stability in 3-D finite-difference time-domain simulations is demonstrated for two piezoelectric crystals: barium sodium niobate and bismuth germanate. Stability is achieved by adapting the discretization grid to meet a central-difference scheme. Stability is demonstrated by showing that the total energy of the piezoelectric system remains constant in the steady state.

  17. 3-D Quantum Transport Solver Based on the Perfectly Matched Layer and Spectral Element Methods for the Simulation of Semiconductor Nanodevices

    PubMed Central

    Cheng, Candong; Lee, Joon-Ho; Lim, Kim Hwa; Massoud, Hisham Z.; Liu, Qing Huo

    2007-01-01

    A 3-D quantum transport solver based on the spectral element method (SEM) and perfectly matched layer (PML) is introduced to solve the 3-D Schrödinger equation with a tensor effective mass. In this solver, the influence of the environment is replaced with the artificial PML open boundary extended beyond the contact regions of the device. These contact regions are treated as waveguides with known incident waves from waveguide mode solutions. As the transmitted wave function is treated as a total wave, there is no need to decompose it into waveguide modes, thus significantly simplifying the problem in comparison with conventional open boundary conditions. The spectral element method leads to an exponentially improving accuracy with the increase in the polynomial order and sampling points. The PML region can be designed such that less than −100 dB outgoing waves are reflected by this artificial material. The computational efficiency of the SEM solver is demonstrated by comparing the numerical and analytical results from waveguide and plane-wave examples, and its utility is illustrated by multiple-terminal devices and semiconductor nanotube devices. PMID:18037971

  18. Improved Artificial Bee Colony Algorithm Based Gravity Matching Navigation Method

    PubMed Central

    Gao, Wei; Zhao, Bo; Zhou, Guang Tao; Wang, Qiu Ying; Yu, Chun Yang

    2014-01-01

    Gravity matching navigation algorithm is one of the key technologies for gravity aided inertial navigation systems. With the development of intelligent algorithms, the powerful search ability of the Artificial Bee Colony (ABC) algorithm makes it possible to be applied to the gravity matching navigation field. However, existing search mechanisms of basic ABC algorithms cannot meet the need for high accuracy in gravity aided navigation. Firstly, proper modifications are proposed to improve the performance of the basic ABC algorithm. Secondly, a new search mechanism is presented in this paper which is based on an improved ABC algorithm using external speed information. At last, modified Hausdorff distance is introduced to screen the possible matching results. Both simulations and ocean experiments verify the feasibility of the method, and results show that the matching rate of the method is high enough to obtain a precise matching position. PMID:25046019

  19. Improved artificial bee colony algorithm based gravity matching navigation method.

    PubMed

    Gao, Wei; Zhao, Bo; Zhou, Guang Tao; Wang, Qiu Ying; Yu, Chun Yang

    2014-07-18

    Gravity matching navigation algorithm is one of the key technologies for gravity aided inertial navigation systems. With the development of intelligent algorithms, the powerful search ability of the Artificial Bee Colony (ABC) algorithm makes it possible to be applied to the gravity matching navigation field. However, existing search mechanisms of basic ABC algorithms cannot meet the need for high accuracy in gravity aided navigation. Firstly, proper modifications are proposed to improve the performance of the basic ABC algorithm. Secondly, a new search mechanism is presented in this paper which is based on an improved ABC algorithm using external speed information. At last, modified Hausdorff distance is introduced to screen the possible matching results. Both simulations and ocean experiments verify the feasibility of the method, and results show that the matching rate of the method is high enough to obtain a precise matching position.

  20. Improved electromagnetic induction processing with novel adaptive matched filter and matched subspace detection

    NASA Astrophysics Data System (ADS)

    Hayes, Charles E.; McClellan, James H.; Scott, Waymond R.; Kerr, Andrew J.

    2016-05-01

    This work introduces two advances in wide-band electromagnetic induction (EMI) processing: a novel adaptive matched filter (AMF) and matched subspace detection methods. Both advances make use of recent work with a subspace SVD approach to separating the signal, soil, and noise subspaces of the frequency measurements The proposed AMF provides a direct approach to removing the EMI self-response while improving the signal to noise ratio of the data. Unlike previous EMI adaptive downtrack filters, this new filter will not erroneously optimize the EMI soil response instead of the EMI target response because these two responses are projected into separate frequency subspaces. The EMI detection methods in this work elaborate on how the signal and noise subspaces in the frequency measurements are ideal for creating the matched subspace detection (MSD) and constant false alarm rate matched subspace detection (CFAR) metrics developed by Scharf The CFAR detection metric has been shown to be the uniformly most powerful invariant detector.

  1. Infrared point target detection with improved template matching

    NASA Astrophysics Data System (ADS)

    Liu, Ruiming; Lu, Yanhong; Gong, Chenglong; Liu, Yang

    2012-07-01

    Detecting point targets in infrared images is a difficult task. Template matching is simple and easy to implement for completing this task. However, it has some shortcomings. We propose an improved template matching method for detecting targets. Different from the classic template matching, the projection coefficients obtained from principal component analysis are used as templates and the nonlinear correlation is proposed to measure the similarity, the matching degree. The correlation in original space can not capture the higher-order statistical property of images. So its detection performance is not satisfying. We introduce the nonlinear correlation, which computes the correlation coefficients in a higher-dimensional feature space or even in an infinite-dimensional feature space, to capture the higher-order statistics. The detection performance is improved greatly. Results of experiments show that the improved method is competent to detect infrared point targets.

  2. Redesigning photo-ID to improve unfamiliar face matching performance.

    PubMed

    White, David; Burton, A Mike; Jenkins, Rob; Kemp, Richard I

    2014-06-01

    Viewers find it difficult to match photos of unfamiliar faces for identity. Despite this, the use of photographic ID is widespread. In this study we ask whether it is possible to improve face matching performance by replacing single photographs on ID documents with multiple photos or an average image of the bearer. In 3 experiments we compare photo-to-photo matching with photo-to-average matching (where the average is formed from multiple photos of the same person) and photo-to-array matching (where the array comprises separate photos of the same person). We consistently find an accuracy advantage for average images and photo arrays over single photos, and show that this improvement is driven by performance in match trials. In the final experiment, we find a benefit of 4-image arrays relative to average images for unfamiliar faces, but not for familiar faces. We propose that conventional photo-ID format can be improved, and discuss this finding in the context of face recognition more generally. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  3. Gun bore flaw image matching based on improved SIFT descriptor

    NASA Astrophysics Data System (ADS)

    Zeng, Luan; Xiong, Wei; Zhai, You

    2013-01-01

    In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

  4. Analysis of an Online Match Discussion Board: Improving the Otolaryngology—Head and Neck Surgery Match

    PubMed Central

    Kozin, Elliott D.; Sethi, Rosh; Lehmann, Ashton; Remenschneider, Aaron K.; Golub, Justin S.; Reyes, Samuel A.; Emerick, Kevin; Lee, Daniel J.; Gray, Stacey T.

    2015-01-01

    Introduction “The Match” has become the accepted selection process for graduate medical education. Otomatch.com has provided an online forum for Otolaryngology-Head and Neck Surgery (OHNS) Match-related questions for over a decade. Herein, we aim to 1) delineate the types of posts on Otomatch to better understand the perspective of medical students applying for residency and 2) provide recommendations to potentially improve the Match process. Methods Discussion forum posts on Otomatch between December 2001 and April 2014 were reviewed. The title of each thread and total number of views were recorded for quantitative analysis. Each thread was organized into one of six major categories and one of eighteen subcategories, based on chronology within the application cycle and topic. National Resident Matching Program (NRMP) data were utilized for comparison. Results We identified 1,921 threads corresponding to over 2 million page views. Over 40% of threads related to questions about specific programs, and 27% were discussions about interviews. Views, a surrogate measure for popularity, reflected different trends. The majority of individuals viewed posts on interviews (42%), program specific questions (20%) and how to rank programs (11%). Increase in viewership tracked with a rise in applicant numbers based on NRMP data. Conclusions Our study provides an in depth analysis of a popular discussion forum for medical students interested in the OHNS Match. The most viewed posts are about interview dates and questions regarding specific programs. We provide suggestions to address unmet needs for medical students and potentially improve the Match process. PMID:25550223

  5. Singing Video Games May Help Improve Pitch-Matching Accuracy

    ERIC Educational Resources Information Center

    Paney, Andrew S.

    2015-01-01

    The purpose of this study was to investigate the effect of singing video games on the pitch-matching skills of undergraduate students. Popular games like "Rock Band" and "Karaoke Revolutions" rate players' singing based on the correctness of the frequency of their sung response. Players are motivated to improve their…

  6. Singing Video Games May Help Improve Pitch-Matching Accuracy

    ERIC Educational Resources Information Center

    Paney, Andrew S.

    2015-01-01

    The purpose of this study was to investigate the effect of singing video games on the pitch-matching skills of undergraduate students. Popular games like "Rock Band" and "Karaoke Revolutions" rate players' singing based on the correctness of the frequency of their sung response. Players are motivated to improve their…

  7. Impedance matched joined drill pipe for improved acoustic transmission

    DOEpatents

    Moss, William C.

    2000-01-01

    An impedance matched jointed drill pipe for improved acoustic transmission. A passive means and method that maximizes the amplitude and minimize the temporal dispersion of acoustic signals that are sent through a drill string, for use in a measurement while drilling telemetry system. The improvement in signal transmission is accomplished by replacing the standard joints in a drill string with joints constructed of a material that is impedance matched acoustically to the end of the drill pipe to which it is connected. Provides improvement in the measurement while drilling technique which can be utilized for well logging, directional drilling, and drilling dynamics, as well as gamma-ray spectroscopy while drilling post shot boreholes, such as utilized in drilling post shot boreholes.

  8. Improvement of EUV mix-match overlay for production implementation

    NASA Astrophysics Data System (ADS)

    Park, Sarohan; Lee, ByoungHoon; Lee, Byong-Seog; Lee, Inwhan; Lim, Chang-Moon

    2016-03-01

    The improvement of overlay control in extreme ultra-violet (EUV) lithography is one of critical issues for successful mass production by using it. Especially it is important to improve the mix and match overlay or matched machine overlay (MMO) between EUV and ArF immersion tool, because EUV process will be applied to specific layers that have more competitive cost edge against ArF immersion multiple patterning with the early mass productivity of EUVL. Therefore it is necessary to consider the EUV overlay target with comparing the overlay specification of double patterning technology (DPT) and spacer patterning technology (SPT). This paper will discuss about required overlay controllability and current performance of EUV, and challenges for future improvement.

  9. Improving the Performance of Perfectly Matched Layers by Means of hp-Adaptivity

    DTIC Science & Technology

    2006-01-01

    of electromagnetic waves, J. Comput. Phys. 114 (1994), 185–200. [4] P. Bettess, Infinite elements, Penshaw Press, 1992. [5] J.H. Bramble and J.E...Computation, (In press), (2006). Preprint available at : http://www.math.tamu.edu/~ bramble /papers.html [6] W.C. Chew, Waves and fields in inhomogeneous media

  10. On the use of INS to improve Feature Matching

    NASA Astrophysics Data System (ADS)

    Masiero, A.; Guarnieri, A.; Vettore, A.; Pirotti, F.

    2014-11-01

    The continuous technological improvement of mobile devices opens the frontiers of Mobile Mapping systems to very compact systems, i.e. a smartphone or a tablet. This motivates the development of efficient 3D reconstruction techniques based on the sensors typically embedded in such devices, i.e. imaging sensors, GPS and Inertial Navigation System (INS). Such methods usually exploits photogrammetry techniques (structure from motion) to provide an estimation of the geometry of the scene. Actually, 3D reconstruction techniques (e.g. structure from motion) rely on use of features properly matched in different images to compute the 3D positions of objects by means of triangulation. Hence, correct feature matching is of fundamental importance to ensure good quality 3D reconstructions. Matching methods are based on the appearance of features, that can change as a consequence of variations of camera position and orientation, and environment illumination. For this reason, several methods have been developed in recent years in order to provide feature descriptors robust (ideally invariant) to such variations, e.g. Scale-Invariant Feature Transform (SIFT), Affine SIFT, Hessian affine and Harris affine detectors, Maximally Stable Extremal Regions (MSER). This work deals with the integration of information provided by the INS in the feature matching procedure: a previously developed navigation algorithm is used to constantly estimate the device position and orientation. Then, such information is exploited to estimate the transformation of feature regions between two camera views. This allows to compare regions from different images but associated to the same feature as seen by the same point of view, hence significantly easing the comparison of feature characteristics and, consequently, improving matching. SIFT-like descriptors are used in order to ensure good matching results in presence of illumination variations and to compensate the approximations related to the estimation

  11. Multiscale real-space quantum-mechanical tight-binding calculations of electronic structure in crystals with defects using perfectly matched layers

    NASA Astrophysics Data System (ADS)

    Pourmatin, Hossein; Dayal, Kaushik

    2016-10-01

    We consider the scattering of incident plane-wave electrons from a defect in a crystal modeled by the time-harmonic Schrödinger equation. While the defect potential is localized, the far-field potential is periodic, unlike standard free-space scattering problems. Previous work on the Schrödinger equation has been almost entirely in free-space conditions; a few works on crystals have been in one-dimension. We construct absorbing boundary conditions for this problem using perfectly matched layers in a tight-binding formulation. Using the example of a point defect in graphene, we examine the efficiency and convergence of the proposed absorbing boundary condition.

  12. Message-passing-interface-based parallel FDTD investigation on the EM scattering from a 1-D rough sea surface using uniaxial perfectly matched layer absorbing boundary.

    PubMed

    Li, J; Guo, L-X; Zeng, H; Han, X-B

    2009-06-01

    A message-passing-interface (MPI)-based parallel finite-difference time-domain (FDTD) algorithm for the electromagnetic scattering from a 1-D randomly rough sea surface is presented. The uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different processors is illustrated for one sea surface realization, and the computation time of the parallel FDTD algorithm is dramatically reduced compared to a single-process implementation. Finally, some numerical results are shown, including the backscattering characteristics of sea surface for different polarization and the bistatic scattering from a sea surface with large incident angle and large wind speed.

  13. Multiscale real-space quantum-mechanical tight-binding calculations of electronic structure in crystals with defects using perfectly matched layers

    SciTech Connect

    Pourmatin, Hossein Dayal, Kaushik

    2016-10-15

    Graphical abstract: - Abstract: We consider the scattering of incident plane-wave electrons from a defect in a crystal modeled by the time-harmonic Schrödinger equation. While the defect potential is localized, the far-field potential is periodic, unlike standard free-space scattering problems. Previous work on the Schrödinger equation has been almost entirely in free-space conditions; a few works on crystals have been in one-dimension. We construct absorbing boundary conditions for this problem using perfectly matched layers in a tight-binding formulation. Using the example of a point defect in graphene, we examine the efficiency and convergence of the proposed absorbing boundary condition.

  14. Perfectly Matched Layer for Galbrun's aeroacoustic equation in a cylindrical coordinates system with an axial and a swirling steady mean flow

    NASA Astrophysics Data System (ADS)

    Baccouche, Ryan; Tahar, Mabrouk Ben; Moreau, Solène

    2016-09-01

    A Perfectly Matched Layer (PML) for aeroacoustic problems using Galbrun's equation in the presence of an axial and a swirling steady mean flow is investigated in a cylindrical coordinates system. This equation is based on an Eulerian-Lagrangian description and leads to a wave equation written only in terms of the Lagrangian perturbation of the displacement. Galbrun's equation is solved by a mixed pressure-displacement Finite Element Method (FEM). To avoid instabilities in the presence of mean flow, a geometric transformation is presented. The validity and efficiency of the proposed PML formulation are established through comparisons with analytical, semi-analytical model based on Pridmore-Brown equation (extended to an axial and a swirling mean flow) and with multiple-scale models. The interest of the formulation is shown through an example of aeroacoustic radiation.

  15. Maximizing switching current of superconductor nanowires via improved impedance matching

    NASA Astrophysics Data System (ADS)

    Zhang, Labao; Yan, Xiachao; Jia, Xiaoqing; Chen, Jian; Kang, Lin; Wu, Peiheng

    2017-02-01

    The temporary resistance triggered by phase slips will result in the switching of a superconductor nanowire to a permanent normal state, decreasing the switching current. In this letter, we propose an improved impedance matching circuit that releases the transition triggered by phase slips to the load resistor through the radio frequency (RF) port of a bias tee. The transportation properties with different load resistors indicate that the switching current decreases due to the reflection caused by impedance mismatching, and it is maximized by optimized impedance matching. Compared to the same setup without the impedance matching circuit, the switching current was increased from 8.0 μA to 12.2 μA in a niobium nitride nanowire after releasing the temporary transition triggered by phase slips. The leakage process with impedance matching outputs a voltage pulse, which enables the user to directly register the transition triggered by phase slips. The technique for maximizing the switching current has a potential practical application in superconductor devices, and the technique for counting phase slips may be applied to explore the behavior of phase slips.

  16. Using lean to improve medication administration safety: in search of the "perfect dose".

    PubMed

    Ching, Joan M; Long, Christina; Williams, Barbara L; Blackmore, C Craig

    2013-05-01

    At Virginia Mason Medical Center (Seattle), the Collaborative Alliance for Nursing Outcomes (CALNOC) Medication Administration Accuracy Quality Study was used in combination with Lean quality improvement efforts to address medication administration safety. Lean interventions were targeted at improving the medication room layout, applying visual controls, and implementing nursing standard work. The interventions were designed to prevent medication administration errors through improving six safe practices: (1) comparing medication with medication administration record, (2) labeling medication, (3) checking two forms of patient identification, (4) explaining medication to patient, (5) charting medication immediately, and (6) protecting the process from distractions/interruptions. Trained nurse auditors observed 9,244 doses for 2,139 patients. Following the intervention, the number of safe-practice violations decreased from 83 violations/100 doses at baseline (January 2010-March 2010) to 42 violations/100 doses at final follow-up (July 2011-September 2011), resulting in an absolute risk reduction of 42 violations/100 doses (95% confidence interval [CI]: 35-48), p < .001). The number of medication administration errors decreased from 10.3 errors/100 doses at baseline to 2.8 errors/100 doses at final follow-up (absolute risk reduction: 7 violations/100 doses [95% CI: 5-10, p < .001]). The "perfect dose" score, reflecting compliance with all six safe practices and absence of any of the eight medication administration errors, improved from 37 in compliance/100 doses at baseline to 68 in compliance/100 doses at the final follow-up. Lean process improvements coupled with direct observation can contribute to substantial decreases in errors in nursing medication administration.

  17. Improved phonocardiogram system based on acoustic impedance matching.

    PubMed

    Schwartz, R S; Reeves, J T; Sodal, I E; Barnes, F S

    1980-04-01

    We considered that phonocardiographic recording could be improved 1) by minimizing the acoustic impedance mismatch between the precordial tissue and transducer, 2) by optimizing the configuration of the impedance-matching medium and transducer design, and 3) by storing signals in digital form through analog-to-digital conversion of analog recordings made at the bedside. The use of an aqueous coupling medium to improve energy transmission increased signal voltage approximately 100-fold over presently used commercial devices. Further match to the crystal was achieved by a concentrating horn configuration for the aqueous medium. Measured frequency response of the device in the range 1 Hz to 1 kHz was better than two other commercially tested microphones. Inspection of comparative phonocardiograms showed more information from the new device than from the two other commercial devices. Unfiltered digitized signals, using our microphone in normal subjects, demonstrated good beat-to-beat repeatability, but analog filtering to obtain the conventional phonocardiogram showed significant loss of information. The new instrument appears to be superior to those commercial devices tested in recording heart sounds.

  18. Modeling of guided circumferential SH and Lamb-type waves in open waveguides with semi-analytical finite element and Perfectly Matched Layer method

    NASA Astrophysics Data System (ADS)

    Matuszyk, Paweł J.

    2017-01-01

    The circumferential guided waves (CGW) are of increasing interest for non-destructive inspecting pipes or other cylindrical structures. If such structures are buried underground, these modes can also deliver some valuable information about the surrounding medium or the quality of the contact between the pipe and the embedding medium. Toward this goal, the detailed knowledge of the dispersive characteristics of CGW is required; henceforth, the robust numerical method has to be established, which allows for the extensive study of the propagation of these modes under different loading conditions. Mathematically, this is the problem of the propagation of guided waves in an open waveguide. This problem differs significantly from the corresponding problem of a closed waveguide both in physical and numerical aspect. The paper presents a combination of semi-analytical finite element method with Perfectly Matched Layer technique for a class of coupled acoustics/elasticity problems with application to modeling of CGW. We discuss different aspects of our algorithm and validate the proposed approach against other established methods available in the literature. The presented numerical examples positively verify the robustness of the proposed method.

  19. Accuracy of pitch matching significantly improved by live voice model.

    PubMed

    Granot, Roni Y; Israel-Kolatt, Rona; Gilboa, Avi; Kolatt, Tsafrir

    2013-05-01

    Singing is, undoubtedly, the most fundamental expression of our musical capacity, yet an estimated 10-15% of Western population sings "out-of-tune (OOT)." Previous research in children and adults suggests, albeit inconsistently, that imitating a human voice can improve pitch matching. In the present study, we focus on the potentially beneficial effects of the human voice and especially the live human voice. Eighteen participants varying in their singing abilities were required to imitate in singing a set of nine ascending and descending intervals presented to them in five different randomized blocked conditions: live piano, recorded piano, live voice using optimal voice production, recorded voice using optimal voice production, and recorded voice using artificial forced voice production. Pitch and interval matching in singing were much more accurate when participants repeated sung intervals as compared with intervals played to them on the piano. The advantage of the vocal over the piano stimuli was robust and emerged clearly regardless of whether piano tones were played live and in full view or were presented via recording. Live vocal stimuli elicited higher accuracy than recorded vocal stimuli, especially when the recorded vocal stimuli were produced in a forced vocal production. Remarkably, even those who would be considered OOT singers on the basis of their performance when repeating piano tones were able to pitch match live vocal sounds, with deviations well within the range of what is considered accurate singing (M=46.0, standard deviation=39.2 cents). In fact, those participants who were most OOT gained the most from the live voice model. Results are discussed in light of the dual auditory-motor encoding of pitch analogous to that found in speech. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  20. Improving fundamental factors among correlation matching algorithms in underwater TANS

    NASA Astrophysics Data System (ADS)

    Lin, Yi; Yan, Lei; Tong, Qingxi

    2007-06-01

    TERCOM, ICP and TIEM algorithms, which mathematically all apply correlation matching mode, have been developed for positioning in underwater Terrain-aided Navigation System (TANS), but how to virtually improve their performance is still research puzzle now. Analyzing the characters of terrain reference data's distribution and vehicles prowling underwater, we find that grid spacing and accumulation sequence are two decisional elements of underwater TANS. Then the modified Maximum a Posteriori (MAP) estimation algorithm (M-MAP) from super-resolution images reconstruction is creatively explored for implementing interpolation to enhance the accuracy of non-surveyed points' deep-determination, and basic error mechanism model (EMM) based on Mean Absolute Difference (MAD) algorithm is deduced which can reflect the relationship of underwater TANS's inner factors. Simulation experiments indicate that adopting appropriate fundamental factors can effectively boost up underwater TANS's navigation competence based on the algorithms listed above.

  1. An improved RANSAC algorithm for line matching on multispectral images

    NASA Astrophysics Data System (ADS)

    Wei, Lijun; Li, Yong; Yu, Hang; Xu, Liangpeng; Fan, Chunxiao

    2017-02-01

    This paper proposes a method for removing mismatched lines on multispectral images. The inaccurate detection of ending points brings a great challenge for matching lines since corresponding lines may not be integrally extracted. Due to the inaccurate detection of ending points, lines are usually mismatched with the line description. To eliminate the mismatched lines, we employ a modified RANSAC (Random Sample Consensus) consisting of two steps: (1) pick three line matches randomly and determine their intersections, which are used to calculate a transformation; (2) the best transformation is obtained by sorting the matching score of line matches and then the inliers are declared as the correct matches. Experimental results show that the proposed method can effectively remove incorrect matches on multispectral images.

  2. Improving statistical analysis of matched case-control studies.

    PubMed

    Conway, Aaron; Rolley, John X; Fulbrook, Paul; Page, Karen; Thompson, David R

    2013-06-01

    Matched case-control research designs can be useful because matching can increase power due to reduced variability between subjects. However, inappropriate statistical analysis of matched data could result in a change in the strength of association between the dependent and independent variables or a change in the significance of the findings. We sought to ascertain whether matched case-control studies published in the nursing literature utilized appropriate statistical analyses. Of 41 articles identified that met the inclusion criteria, 31 (76%) used an inappropriate statistical test for comparing data derived from case subjects and their matched controls. In response to this finding, we developed an algorithm to support decision-making regarding statistical tests for matched case-control studies.

  3. Improving the Quality of the Supply-Demand-Match in Vocational Education and Training by Anticipation and "Matching Policy"

    ERIC Educational Resources Information Center

    Lassnigg, Lorenz

    2008-01-01

    This article discusses the implications of a framework to improve matching supply and demand in VET by a policy to improve quality by using anticipation and foresight approaches. Analysis of the Austrian anticipation system identified some basic aspects such as policy. The analysis focused on two issues: the observation and measurement of…

  4. A placebo-controlled, double-blind clinical trial to evaluate the efficacy of Imedeen(®) Time Perfection(®) for improving the appearance of photodamaged skin.

    PubMed

    Stephens, Thomas J; Sigler, Monya L; Herndon, James H; Dispensa, Lisa; Le Moigne, Anne

    2016-01-01

    To assess the efficacy of Imedeen Time Perfection for improving the appearance and condition of photoaged skin in healthy women. This randomized, double-blind, placebo-controlled clinical trial enrolled healthy women, 35-60 years of age, with Fitzpatrick I-III and Glogau II-III skin types and mild-to-moderate facial fine lines/wrinkles. The eligible subjects were randomized to receive two tablets daily of either Imedeen Time Perfection (Imedeen) or a matching placebo for 12 weeks. Efficacy assessments included investigator rating of 16 photoaging parameters (ie, global facial appearance and 15 individual facial parameters and the average of all parameters), instrumentation (ie, ultrasound dermal density, moisture level of the stratum corneum, transepidermal water loss, cutometry), and subjects' self-assessment. Differences in the mean change from baseline to week 12 values on these outcomes were compared between Imedeen and placebo using analysis of variance or a paired t-test. Seventy-four subjects with primarily Fitzpatrick skin type III (78%-79%) and Glogau type III (53%-58%) completed the study (Imedeen: n=36; placebo: n=38). The mean difference in change from baseline to week 12 for global facial assessment significantly favored Imedeen over placebo (-0.52; P=0.0017). Additionally, the mean differences in the average of all facial photoaging parameters (-0.29), mottled hyperpigmentation (-0.25), tactile laxity (-0.24), dullness (-0.47), and tactile roughness (-0.62) significantly favored Imedeen over placebo (P≤0.05). Significantly greater increases in ultrasound dermal density (+11% vs +1%; P≤0.05) and stratum corneum moisturization (+30% vs +6%; P≤0.05) were also observed for Imedeen than for placebo. There were no significant differences on other instrumental outcomes. The results of this study suggest that Imedeen Time Perfection can positively affect the appearance of photoaged skin, moisturization, and skin density over 12 weeks of treatment.

  5. Improved Real-Time Scan Matching Using Corner Features

    NASA Astrophysics Data System (ADS)

    Mohamed, H. A.; Moussa, A. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, Abu B.

    2016-06-01

    The automation of unmanned vehicle operation has gained a lot of research attention, in the last few years, because of its numerous applications. The vehicle localization is more challenging in indoor environments where absolute positioning measurements (e.g. GPS) are typically unavailable. Laser range finders are among the most widely used sensors that help the unmanned vehicles to localize themselves in indoor environments. Typically, automatic real-time matching of the successive scans is performed either explicitly or implicitly by any localization approach that utilizes laser range finders. Many accustomed approaches such as Iterative Closest Point (ICP), Iterative Matching Range Point (IMRP), Iterative Dual Correspondence (IDC), and Polar Scan Matching (PSM) handles the scan matching problem in an iterative fashion which significantly affects the time consumption. Furthermore, the solution convergence is not guaranteed especially in cases of sharp maneuvers or fast movement. This paper proposes an automated real-time scan matching algorithm where the matching process is initialized using the detected corners. This initialization step aims to increase the convergence probability and to limit the number of iterations needed to reach convergence. The corner detection is preceded by line extraction from the laser scans. To evaluate the probability of line availability in indoor environments, various data sets, offered by different research groups, have been tested and the mean numbers of extracted lines per scan for these data sets are ranging from 4.10 to 8.86 lines of more than 7 points. The set of all intersections between extracted lines are detected as corners regardless of the physical intersection of these line segments in the scan. To account for the uncertainties of the detected corners, the covariance of the corners is estimated using the extracted lines variances. The detected corners are used to estimate the transformation parameters between the

  6. Improved Feature Matching for Mobile Devices with IMU

    PubMed Central

    Masiero, Andrea; Vettore, Antonio

    2016-01-01

    Thanks to the recent diffusion of low-cost high-resolution digital cameras and to the development of mostly automated procedures for image-based 3D reconstruction, the popularity of photogrammetry for environment surveys is constantly increasing in the last years. Automatic feature matching is an important step in order to successfully complete the photogrammetric 3D reconstruction: this step is the fundamental basis for the subsequent estimation of the geometry of the scene. This paper reconsiders the feature matching problem when dealing with smart mobile devices (e.g., when using the standard camera embedded in a smartphone as imaging sensor). More specifically, this paper aims at exploiting the information on camera movements provided by the inertial navigation system (INS) in order to make the feature matching step more robust and, possibly, computationally more efficient. First, a revised version of the affine scale-invariant feature transform (ASIFT) is considered: this version reduces the computational complexity of the original ASIFT, while still ensuring an increase of correct feature matches with respect to the SIFT. Furthermore, a new two-step procedure for the estimation of the essential matrix E (and the camera pose) is proposed in order to increase its estimation robustness and computational efficiency. PMID:27527186

  7. Improved Feature Matching for Mobile Devices with IMU.

    PubMed

    Masiero, Andrea; Vettore, Antonio

    2016-08-05

    Thanks to the recent diffusion of low-cost high-resolution digital cameras and to the development of mostly automated procedures for image-based 3D reconstruction, the popularity of photogrammetry for environment surveys is constantly increasing in the last years. Automatic feature matching is an important step in order to successfully complete the photogrammetric 3D reconstruction: this step is the fundamental basis for the subsequent estimation of the geometry of the scene. This paper reconsiders the feature matching problem when dealing with smart mobile devices (e.g., when using the standard camera embedded in a smartphone as imaging sensor). More specifically, this paper aims at exploiting the information on camera movements provided by the inertial navigation system (INS) in order to make the feature matching step more robust and, possibly, computationally more efficient. First, a revised version of the affine scale-invariant feature transform (ASIFT) is considered: this version reduces the computational complexity of the original ASIFT, while still ensuring an increase of correct feature matches with respect to the SIFT. Furthermore, a new two-step procedure for the estimation of the essential matrix E (and the camera pose) is proposed in order to increase its estimation robustness and computational efficiency.

  8. A More Perfect Union

    ERIC Educational Resources Information Center

    DiConsiglio, John

    2012-01-01

    Alumni relations and stewardship officers have the makings of a strong partnership. Alumni relations and stewardship can be a natural fit--a perfect match even--according to Mary Jo Chiara of St. Joseph's College (SJC) in New York. Both strive to cultivate long-term relationships with constituents and build increasing levels of engagement and…

  9. A placebo-controlled, double-blind clinical trial to evaluate the efficacy of Imedeen® Time Perfection® for improving the appearance of photodamaged skin

    PubMed Central

    Stephens, Thomas J; Sigler, Monya L; Herndon, James H; Dispensa, Lisa; Le Moigne, Anne

    2016-01-01

    Objective To assess the efficacy of Imedeen Time Perfection for improving the appearance and condition of photoaged skin in healthy women. Methods This randomized, double-blind, placebo-controlled clinical trial enrolled healthy women, 35–60 years of age, with Fitzpatrick I–III and Glogau II–III skin types and mild-to-moderate facial fine lines/wrinkles. The eligible subjects were randomized to receive two tablets daily of either Imedeen Time Perfection (Imedeen) or a matching placebo for 12 weeks. Efficacy assessments included investigator rating of 16 photoaging parameters (ie, global facial appearance and 15 individual facial parameters and the average of all parameters), instrumentation (ie, ultrasound dermal density, moisture level of the stratum corneum, transepidermal water loss, cutometry), and subjects’ self-assessment. Differences in the mean change from baseline to week 12 values on these outcomes were compared between Imedeen and placebo using analysis of variance or a paired t-test. Results Seventy-four subjects with primarily Fitzpatrick skin type III (78%–79%) and Glogau type III (53%–58%) completed the study (Imedeen: n=36; placebo: n=38). The mean difference in change from baseline to week 12 for global facial assessment significantly favored Imedeen over placebo (−0.52; P=0.0017). Additionally, the mean differences in the average of all facial photoaging parameters (−0.29), mottled hyperpigmentation (−0.25), tactile laxity (−0.24), dullness (−0.47), and tactile roughness (−0.62) significantly favored Imedeen over placebo (P≤0.05). Significantly greater increases in ultrasound dermal density (+11% vs +1%; P≤0.05) and stratum corneum moisturization (+30% vs +6%; P≤0.05) were also observed for Imedeen than for placebo. There were no significant differences on other instrumental outcomes. Conclusion The results of this study suggest that Imedeen Time Perfection can positively affect the appearance of photoaged skin

  10. Refractive index matching improves optical object detection in paper

    NASA Astrophysics Data System (ADS)

    Saarela, J. M. S.; Heikkinen, S. M.; Fabritius, T. E. J.; Haapala, A. T.; Myllylä, R. A.

    2008-05-01

    The demand for high-quality recycled pulp products has increased the need for an efficient deinking process. Assessing process efficiency via residual ink on test sheets has so far been limited to the sheet surface due to the poor transparency of paper. A refractive index matching method was studied to obtain a quantitative measure of particles within the volume of a paper sheet. In actual measurements a glass plate with etched lines from 8.5 µm to 281.1 µm wide was placed beneath the layers of cleared paper, and visible lines were counted with a microscope. Three different paper grades were tested with transparentizing agents. A diffusion theory-based regression model was used to find a correlation between transparency, paper grammage and paper thickness. These equations enable the determination of the size of an object detectable from a paper with a certain transparentizing agent or the parameters of a test sheet needed to detect objects of a known size. Anise oil was found to be the better of the two agents used, and they both had better transparentizing ability than air or water. The transparent paper grammage of the paper grades was determined for all the tested media. Paper's transparency was found to depend more on paper's thickness than grammage.

  11. Hematopoietic stem cell transplantation donor sources in the 21st century: choosing the ideal donor when a perfect match does not exist.

    PubMed

    Kekre, Natasha; Antin, Joseph H

    2014-07-17

    Most patients who require allogeneic stem cell transplantation do not have a matched sibling donor, and many patients do not have a matched unrelated donor. In an effort to increase the applicability of transplantation, alternative donors such as mismatched adult unrelated donors, haploidentical related donors, and umbilical cord blood stem cell products are frequently used when a well matched donor is unavailable. We do not yet have the benefit of randomized trials comparing alternative donor stem cell sources to inform the choice of donor; however, the existing data allow some inferences to be made on the basis of existing observational and phase 2 studies. All 3 alternative donor sources can provide effective lymphohematopoietic reconstitution, but time to engraftment, graft failure rate, graft-versus-host disease, transplant-related mortality, and relapse risk vary by donor source. These factors all contribute to survival outcomes and an understanding of them should help guide clinicians when choosing among alternative donor sources when a matched related or matched unrelated donor is not available. © 2014 by The American Society of Hematology.

  12. Imperfect practice makes perfect: error management training improves transfer of learning.

    PubMed

    Dyre, Liv; Tabor, Ann; Ringsted, Charlotte; Tolsgaard, Martin G

    2017-02-01

    Traditionally, trainees are instructed to practise with as few errors as possible during simulation-based training. However, transfer of learning may improve if trainees are encouraged to commit errors. The aim of this study was to assess the effects of error management instructions compared with error avoidance instructions during simulation-based ultrasound training. Medical students (n = 60) with no prior ultrasound experience were randomised to error management training (EMT) (n = 32) or error avoidance training (EAT) (n = 28). The EMT group was instructed to deliberately make errors during training. The EAT group was instructed to follow the simulator instructions and to commit as few errors as possible. Training consisted of 3 hours of simulation-based ultrasound training focusing on fetal weight estimation. Simulation-based tests were administered before and after training. Transfer tests were performed on real patients 7-10 days after the completion of training. Primary outcomes were transfer test performance scores and diagnostic accuracy. Secondary outcomes included performance scores and diagnostic accuracy during the simulation-based pre- and post-tests. A total of 56 participants completed the study. On the transfer test, EMT group participants attained higher performance scores (mean score: 67.7%, 95% confidence interval [CI]: 62.4-72.9%) than EAT group members (mean score: 51.7%, 95% CI: 45.8-57.6%) (p < 0.001; Cohen's d = 1.1, 95% CI: 0.5-1.7). There was a moderate improvement in diagnostic accuracy in the EMT group compared with the EAT group (16.7%, 95% CI: 10.2-23.3% weight deviation versus 26.6%, 95% CI: 16.5-36.7% weight deviation [p = 0.082; Cohen's d = 0.46, 95% CI: -0.06 to 1.0]). No significant interaction effects between group and performance improvements between the pre- and post-tests were found in either performance scores (p = 0.25) or diagnostic accuracy (p = 0.09). The provision of error management instructions during simulation

  13. An improved broadband matched field processor for geoacoustic inversion (L).

    PubMed

    Tolstoy, A

    2012-10-01

    The approach proposed here requires that for each parameter combination in a search space only a minimum processor value (over frequencies) be retained. Thus all frequencies considered at that point will have processor values at least as great as the final value. Consequently, (1) the frequency most sensitive to a parameter dominates the search automatically and (2) resolution has improved with major sidelobe reduction. The method is intended primarily for geoacoustic inversion methods (where the signal-to-noise levels are high).

  14. Electrospun Vascular Grafts with Improved Compliance Matching to Native Vessels

    PubMed Central

    Nezarati, Roya M.; Eifert, Michelle B.; Dempsey, David K.; Cosgriff-Hernandez, Elizabeth

    2014-01-01

    Coronary artery bypass grafting (CABG) is one of the most commonly performed major surgeries in the United States. Autologous vessels such as the saphenous vein are the current gold standard for treatment; however, synthetic vascular prostheses made of expanded poly(tetrafluoroethylene) (ePTFE) or poly(ethylene terephthalate) (PET) are used when autologous vessels are unavailable. These synthetic grafts have a high failure rate in small diameter (<4 mm) applications due to rapid re-occlusion via intimal hyperplasia. Current strategies to improve clinical performance are focused on preventing intimal hyperplasia by fabricating grafts with compliance and burst pressure similar to native vessels. To this end, we have developed an electrospun vascular graft from segmented polyurethanes with tunable properties by altering material chemistry and graft microarchitecture. Relationships between polyurethane tensile properties and biomechanical properties were elucidated to select polymers with desirable properties. Graft thickness, fiber tortuosity, and fiber fusions were modulated to provide additional tools for controlling graft properties. Using a combination of these strategies, a vascular graft with compliance and burst pressure exceeding the saphenous vein autograft was fabricated (compliance = 6.0 ± 0.6 %/mmHg × 10−4, burst pressure = 2260 ± 160 mmHg). This graft is hypothesized to reduce intimal hyperplasia associated with low compliance in synthetic grafts and improve long term clinical success. Additionally, the fundamental relationships between electrospun mesh microarchitecture and mechanical properties identified in this work can be utilized in various biomedical applications. PMID:24846218

  15. Using Local Matching to Improve Estimates of Program Impact: Evidence from Project STAR

    ERIC Educational Resources Information Center

    Jones, Nathan; Steiner, Peter; Cook, Tom

    2011-01-01

    In this study the authors test whether matching using intact local groups improves causal estimates over those produced using propensity score matching at the student level. Like the recent analysis of Wilde and Hollister (2007), they draw on data from Project STAR to estimate the effect of small class sizes on student achievement. They propose a…

  16. Missile placement analysis based on improved SURF feature matching algorithm

    NASA Astrophysics Data System (ADS)

    Yang, Kaida; Zhao, Wenjie; Li, Dejun; Gong, Xiran; Sheng, Qian

    2015-03-01

    The precious battle damage assessment by use of video images to analysis missile placement is a new study area. The article proposed an improved speeded up robust features algorithm named restricted speeded up robust features, which combined the combat application of TV-command-guided missiles and the characteristics of video image. Its restrictions mainly reflected in two aspects, one is to restrict extraction area of feature point; the second is to restrict the number of feature points. The process of missile placement analysis based on video image was designed and a video splicing process and random sample consensus purification were achieved. The RSURF algorithm is proved that has good realtime performance on the basis of guarantee the accuracy.

  17. Does Practice Make Perfect? Role of Training and Feedback in Improving Scientists' Presentation Skills

    NASA Astrophysics Data System (ADS)

    Tankersley, R. A.; Bourexis, P.; Kaser, J. S.

    2011-12-01

    Within the research and academic communities there is a growing interest in improving the communication skills of scientists, especially their ability to communicate the substance and importance of their research to general audiences. To address this need, we developed an intensive, two-day workshop [Presentation Boot Camp (PBC)] that focuses on presenting scientific concepts and research findings more effectively to both scientific/technical audiences and the general public. Through a series of interactive sessions, participants receive training in planning and preparing presentations that communicate messages more clearly and effectively and that have a lasting impact on the audience. Topics include: knowing and identifying the needs of the audience, highlighting big ideas and take-home messages, designing effective visuals, decoding complex concepts with diagrams, and displaying data in meaningful ways. PBC attendees also receive training in the use and application of the Presentation Skills Protocol (PSP) and associated rubric for evaluating the effectiveness of scientific presentations. The PSP was originally developed as part of a NSF Graduate Teaching Fellows in K-12 Education Program (GK-12) to assess and track the impact of the GK-12 experience on the communication skills of Graduate Teaching Fellows. The PSP focuses on eleven presentation skill sets, including organization, accuracy, relevance, message, language, equity, delivery, technology, use of time, questions, and presence. The associated rubric operationally defines each of the skill sets at three categorical levels of competence: (1) proficient, (2) developing, and (3) needs attention. The PSP may be used to (1) provide scientists with regular and consistent feedback on the quality and effectiveness of their classroom and research presentations and (2) design professional development activities and training programs that target specific presentation skills. However, our evaluation results indicate

  18. The perfect storm: match-mismatch of bio-physical events drives larval reef fish connectivity between Pulley Ridge and the Florida Keys

    NASA Astrophysics Data System (ADS)

    Vaz, A.; Paris, C. B.; Olascoaga, M. J.; Kourafalou, V.; Kang, H.

    2016-02-01

    Mesophotic reefs have been hypothesized to act as a refugia, by exporting larvae to more vulnerable shallow water reefs and potentially aiding the replenishment of disturbed populations. Despite the fundamental role of mesophotic reef for the recovery and conservation of shallow water reef ecosystems, the spatio-temporal extent of such connections is currently unresolved. Here we aim to explore the underlaying mechanisms of the connections between a mesophotic reef, the Pulley Ridge, and the shallow water Florida Keys reefs, by simulating the dispersal of the bicolor damselfish, Stegastes partitus. We use the Connectivity Modeling System (CMS) of the University of Miami, an open-source individual-based model, and present new biophysical modeling code to allow a realistic representation of 3-dimensional discreet coral reef habitats and investigate vertical connectivity. Virtual larvae are released and tracked within a fine resolution ( 900m) hydrodynamic model until their settlement. S. partitus biological traits such as spawning periodicity, mortality and vertical migration are also incorporated on the model. Probabilistic simulations indicate mesophotic-shallow connections, with larvae spawned at Pulley Ridge reaching the Florida Keys settlement grounds during sporadic settlement pulses. These "perfect storm" settlement events are modulated by the co-occurence of larval traits with physical processes, particularly by the interaction of ontogenetic vertical migration and the Florida Current fronts and cyclonic eddies. This demonstrates that mesophotic coral reef ecosystems can also serve as a refugia for coral reef fish and suggests that they could increase the resilience of their shallow counterpart.

  19. The perfect storm: Match-mismatch of bio-physical events drives larval reef fish connectivity between Pulley Ridge mesophotic reef and the Florida Keys

    NASA Astrophysics Data System (ADS)

    Vaz, Ana C.; Paris, Claire B.; Olascoaga, M. Josefina; Kourafalou, Villy H.; Kang, Heesook; Reed, John K.

    2016-08-01

    Mesophotic coral reef ecosystems are remote from coastal stressors, but are still vulnerable to over-exploitation, and remain mostly unprotected. They may be the key to coral reefs resilience, yet little is known about the pattern of larval subsidies from deeper to shallower coral reef habitats. Here we use a biophysical modeling approach to test the hypothesis that fishes from mesophotic coral reef ecosystems may replenish shallow reef populations. We aim at identifying the spatio-temporal patterns and underlying mechanisms of larval connections between Pulley Ridge, a mesophotic reef in the Gulf of Mexico hosting of a variety of shallow-water tropical fishes, and the Florida Keys reefs. A new three-dimensional (3D) polygon habitat module is developed for the open-source Connectivity Modeling System to simulate larval movement behavior of the bicolor damselfish, Stegastes partitus, in a realistic 3D representation of the coral reef habitat. Biological traits such as spawning periodicity, mortality, and vertical migration are also incorporated in the model. Virtual damselfish larvae are released daily from the Pulley Ridge at 80 m depth over 60 lunar spawning cycles and tracked until settlement within a fine resolution (~900 m) hydrodynamic model of the region. Such probabilistic simulations reveal mesophotic-shallow connections with large, yet sporadic pulses of larvae settling in the Florida Keys. Modal and spectral analyses on the spawning time of successful larvae, and on the position of the Florida Current front with respect to Pulley Ridge, demonstrate that specific physical-biological interactions modulate these "perfect storm" events. Indeed, the co-occurrence of (1) peak spawning with frontal features, and (2) cyclonic eddies with ontogenetic vertical migration, contribute to high settlement in the Florida Keys. This study demonstrates that mesophotic coral reef ecosystems can also serve as refugia for coral reef fish and suggests that they have a critical

  20. Improved particle size estimation in digital holography via sign matched filtering.

    PubMed

    Lu, Jiang; Shaw, Raymond A; Yang, Weidong

    2012-06-04

    A matched filter method is provided for obtaining improved particle size estimates from digital in-line holograms. This improvement is relative to conventional reconstruction and pixel counting methods for particle size estimation, which is greatly limited by the CCD camera pixel size. The proposed method is based on iterative application of a sign matched filter in the Fourier domain, with sign meaning the matched filter takes values of ±1 depending on the sign of the angular spectrum of the particle aperture function. Using simulated data the method is demonstrated to work for particle diameters several times the pixel size. Holograms of piezoelectrically generated water droplets taken in the laboratory show greatly improved particle size measurements. The method is robust to additive noise and can be applied to real holograms over a wide range of matched-filter particle sizes.

  1. Mimicry Is Presidential: Linguistic Style Matching in Presidential Debates and Improved Polling Numbers.

    PubMed

    Romero, Daniel M; Swaab, Roderick I; Uzzi, Brian; Galinsky, Adam D

    2015-10-01

    The current research used the contexts of U.S. presidential debates and negotiations to examine whether matching the linguistic style of an opponent in a two-party exchange affects the reactions of third-party observers. Building off communication accommodation theory (CAT), interaction alignment theory (IAT), and processing fluency, we propose that language style matching (LSM) will improve subsequent third-party evaluations because matching an opponent's linguistic style reflects greater perspective taking and will make one's arguments easier to process. In contrast, research on status inferences predicts that LSM will negatively impact third-party evaluations because LSM implies followership. We conduct two studies to test these competing hypotheses. Study 1 analyzed transcripts of U.S. presidential debates between 1976 and 2012 and found that candidates who matched their opponent's linguistic style increased their standing in the polls. Study 2 demonstrated a causal relationship between LSM and third-party observer evaluations using negotiation transcripts.

  2. Using a Spanish Surname Match to Improve Identification of Hispanic Women in Medicare Administrative Data

    PubMed Central

    Wei, Iris I; Virnig, Beth A; John, Dolly A; Morgan, Robert O

    2006-01-01

    Objective To assess the effectiveness of a Spanish surname match for improving the identification of Hispanic women in Medicare administrative data in which Hispanics are historically underrepresented. Data Sources We collected self-identified race/ethnicity data (N = 2,997) from a mailed survey sent to elderly Medicare beneficiaries who resided in 11 geographic areas consisting of eight metropolitan counties and three nonmetropolitan areas (171 counties) in the fall of 2004. The 1990 Census Spanish Surname list was used to identify Hispanics in the Medicare data. In addition, we used data published on the U.S. Census Bureau website to obtain estimates of elderly Hispanics. Study Design We used self-identified race/ethnicity as the gold standard to examine the agreement with Medicare race code alone, and with Medicare race code+Spanish surname match. Additionally, we estimated the proportions of Hispanic women and men, in each of the 11 geographic areas in our survey, using the Medicare race code alone and the Medicare race code+Spanish surname match, and compared those estimates with estimates derived from U.S. Census 2000 data. Principal Findings The Spanish surname match dramatically increased the accuracy of the Medicare race code for identifying both Hispanic and white women, producing improvements comparable with those seen for men. Conclusions We recommend the addition of a proxy race code in the Medicare data using the Spanish surname match to improve the accuracy of racial/ethnic representation. PMID:16899019

  3. Multi-Source Remote Sensing Images Matching Based on Improved Kaze Algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Z.-W.; Wang, H. B.; Wang, G.-H.; Li, C.-H.; Yang, H. C.

    2013-07-01

    SIFT as the representative of the same feature point extraction and matching algorithm has been widely applied in the field of multisource remote sensing image matching. However, it eliminates noise and detects features at different scale levels by building or approximating the Gaussian scale space based on linear. Gaussian blurring does not respect the natural boundaries of objects and smoothes to the same degree details and noise, reducing localization accuracy. To solve this problem, we proposed an improved KAZE algorithm which can build stable nonlinear scale space. Firstly, the extreme points are detected through building stable nonlinear scale space. Secondly, The match result by optimizing the feature points and strictly limiting matching threshold is used to calculate geometric transformation model parameters between two image. Finally, we can use this geometric transformation model to restrict the search space for feature points matching. Experimental results show that the improved KAZE algorithm is significantly better than the before KAZE. Moreover, for detail and texture blurred images, KAZE and its improved algorithm have unique advantages compared to the SIFT.

  4. Sensor-Based Vibration Signal Feature Extraction Using an Improved Composite Dictionary Matching Pursuit Algorithm

    PubMed Central

    Cui, Lingli; Wu, Na; Wang, Wenjing; Kang, Chenhui

    2014-01-01

    This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP) algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP) is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and reconstruction algorithm

  5. Sensor-based vibration signal feature extraction using an improved composite dictionary matching pursuit algorithm.

    PubMed

    Cui, Lingli; Wu, Na; Wang, Wenjing; Kang, Chenhui

    2014-09-09

    This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP) algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP) is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and reconstruction algorithm

  6. [Application of an improved model of a job-matching platform for nurses].

    PubMed

    Huang, Way-Ren; Lin, Chiou-Fen

    2015-04-01

    The three-month attrition rate for new nurses in Taiwan remains high. Many hospitals rely on traditional recruitment methods to find new nurses, yet it appears that their efficacy is less than ideal. To effectively solve this manpower shortage, a nursing resource platform is a project worth developing in the future. This study aimed to utilize a quality-improvement model to establish communication between hospitals and nursing students and create a customized employee-employer information-matching platform to help nursing students enter the workforce. This study was structured around a quality-improvement model and used current situation analysis, literature review, focus-group discussions, and process re-engineering to formulate necessary content for a job-matching platform for nursing. The concept of an academia-industry strategic alliance helped connect supply and demand within the same supply chain. The nurse job-matching platform created in this study provided job flexibility as well as job suitability assessments and continued follow-up and services for nurses after entering the workforce to provide more accurate matching of employers and employees. The academia-industry strategic alliance, job suitability, and long-term follow-up designed in this study are all new features in Taiwan's human resource service systems. The proposed human resource process re-engineering provides nursing students facing graduation with a professionally managed human resources platform. Allowing students to find an appropriate job prior to graduation will improve willingness to work and employee retention.

  7. Neuroplasticity and MRI: A perfect match.

    PubMed

    Hamaide, Julie; De Groof, Geert; Van der Linden, Annemie

    2016-05-01

    Numerous studies have illustrated the benefits of physical workout and cognitive exercise on brain function and structure and, more importantly, on decelerating cognitive decline in old age and promoting functional rehabilitation following injury. Despite these behavioral observations, the exact mechanisms underlying these neuroplastic phenomena remain obscure. This gap illustrates the need for carefully designed in-depth studies using valid models and translational tools which allow to uncover the observed events up to the molecular level. We promote the use of in vivo magnetic resonance imaging (MRI) because it is a powerful translational imaging technique able to extract functional, structural, and biochemical information from the entire brain. Advanced processing techniques allow performing voxel-based analyses which are capable of detecting novel loci implicated in specific neuroplastic events beyond traditional regions-of-interest analyses. In addition, its non-invasive character sets it as currently the best global imaging tool for performing dynamic longitudinal studies on the same living subject, allowing thus exploring the effects of experience, training, treatment etc. in parallel to additional measures such as age, cognitive performance scores, hormone levels, and many others. The aim of this review is (i) to introduce how different animal models contributed to extend the knowledge on neuroplasticity in both health and disease, over different life stages and upon various experiences, and (ii) to illustrate how specific MRI techniques can be applied successfully to inform on the fundamental mechanisms underlying experience-dependent or activity-induced neuroplasticity including cognitive processes.

  8. Improved diagnostics by automated matching and enhancement in fluorescein angiography of the ocular fundus

    NASA Astrophysics Data System (ADS)

    Noordmans, Herke Jan; van den Biesen, Pieter; de Roode, Rowland; Verdaasdonk, Rudolf

    2008-02-01

    An interactive image matching program has been developed to help ophthalmologists in perceiving subtle differences between sequential images obtained during fluorescein angiography. In a pilot experiment, it appeared that the image matching program could effectively correct camera alignment errors. By offering simple tools like image overlay, blinking and image subtraction, differences between angiograms can be greatly enhanced and interpreted. It appeared that newly formed, leaking blood vessels could be detected at an earlier stage of the disease process using these tools. Treatment can be initiated right away, thereby preventing the patient from having additional visual loss. The matching program seems to improve the quality of fundus diagnostics but needs to be validated in future studies.

  9. Speed improvements of peptide-spectrum matching using single-instruction multiple-data instructions.

    PubMed

    Zhang, Jian; McQuillan, Ian; Wu, Fang-Xiang

    2011-10-01

    Peptide-spectrum matching is one of the most time-consuming portion of the database search method for assignment of tandem mass spectra to peptides. In this study, we develop a parallel algorithm for peptide-spectrum matching using Single-Instruction Multiple Data (SIMD) instructions. Unlike other parallel algorithms in peptide-spectrum matching, our algorithm parallelizes the computation of matches between a single spectrum and a given peptide sequence from the database. It also significantly reduces the number of comparison operations. Extra improvements are obtained by using SIMD instructions to avoid conditional branches and unnecessary memory access within the algorithm. The implementation of the developed algorithm is based on the Streaming SIMD Extensions technology that is embedded in most Intel microprocessors. Similar technology also exists in other modern microprocessors. A simulation shows that the developed algorithm achieves an 18-fold speedup over the previous version of Real-Time Peptide-Spectrum Matching algorithm [F. X. Wu et al., Rapid Commun. Mass Sepctrom. 2006, 20, 1199-1208]. Therefore, the developed algorithm can be employed to develop real-time control methods for MS/MS.

  10. An improved finger-vein recognition algorithm based on template matching

    NASA Astrophysics Data System (ADS)

    Liu, Yueyue; Di, Si; Jin, Jian; Huang, Daoping

    2016-10-01

    Finger-vein recognition has became the most popular biometric identify methods. The investigation on the recognition algorithms always is the key point in this field. So far, there are many applicable algorithms have been developed. However, there are still some problems in practice, such as the variance of the finger position which may lead to the image distortion and shifting; during the identification process, some matching parameters determined according to experience may also reduce the adaptability of algorithm. Focus on above mentioned problems, this paper proposes an improved finger-vein recognition algorithm based on template matching. In order to enhance the robustness of the algorithm for the image distortion, the least squares error method is adopted to correct the oblique finger. During the feature extraction, local adaptive threshold method is adopted. As regard as the matching scores, we optimized the translation preferences as well as matching distance between the input images and register images on the basis of Naoto Miura algorithm. Experimental results indicate that the proposed method can improve the robustness effectively under the finger shifting and rotation conditions.

  11. An improved SIFT algorithm in the application of close-range Stereo image matching

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Wang, Xiaoqing; Yuan, Xiaoxiang; Wang, Shumin

    2016-11-01

    As unmanned aerial vehicle (UAV) remote sensing is applied in small area aerial photogrammetry surveying, disaster monitoring and emergency command, 3D urban construction and other fields, the image processing of UAV has become a hot topic in current research. The precise matching of UAV image is a key problem, which affects the subsequent processing precision directly, such as 3D reconstruction and automatic aerial triangulation, etc. At present, SIFT (Scale Invariant Feature Transform) algorithm proposed by DAVID G. LOWE as the main method is, is widely used in image matching, since its strong stability to image rotation, shift, scaling, and the change of illumination conditions. It has been successfully applied in target recognition, SFM (Structure from Motion), and many other fields. SIFT algorithm needs the colour images to be converted into grayscale images, detects extremum points under different scales and uses neighbourhood pixels to generate descriptor. As we all know that UAV images with rich colour information, the SIFT algorithm improved through combining with the image colour information in this paper, the experiments are conducted from matching efficiency and accuracy compared with the original SIFT algorithm. The results show that the method which proposed in this paper decreases on the efficiency, but is improved on the precision and provides a basis choice for matching method.

  12. Spectral matching in Hyperion images for improved characterization of Mangrove ecosystems in southern India

    NASA Astrophysics Data System (ADS)

    Padma, S.; Sanjeevi, S.

    2014-11-01

    Mangrove ecosystem study is one of the main beneficiaries of the application of hyperspectral data and spectral matching techniques. Diversity and density of mangrove species leads to complexity of the ecosystem. Hence, species level mapping becomes difficult. Though hyperspectral images are appropriate for such a mapping, different mangrove species with closely matching spectra pose a challenge. This paper proposes a novel hyperspectral matching algorithm by integrating the stochastic Jeffries-Matusita measure (JM) and deterministic Spectral Angle Mapper (SAM) to accurately map most species of the mangrove ecosystem. The JM-SAM algorithm signifies the combination of an quantitative angle measure (SAM) and an qualitative distance measure (JM). The spectral capabilities of both the measures are orthogonally projected using tangent and sine functions to result in the combined algorithm. The developed JM-SAM algorithm is implemented to discriminate the mangrove species and the landcover classes of Pichavaram and Muthupet mangrove forests of southern India using the Hyperion datasets. The developed algorithm is extended in a supervised framework for improved classification of the Hyperion image. The reference spectra of the mangrove species and other cover types are extracted from the Hyperion image. From the values of relative spectral discriminatory probability and relative discriminatory entropy value, it can be inferred that hybrid JM-SAM matching measure results in improved discriminability than the individual SAM and JM algorithms. This performance is reflected in the classification results where the JM-SAM (TAN) and JM-SAM (SIN) matching algorithms yielded an improved accuracy of (86.25%,85%) and (88.10%, 86.96) for both the study sites.

  13. Improvement of retinal blood vessel detection by spur removal and Gaussian matched filtering compensation

    NASA Astrophysics Data System (ADS)

    Xiao, Di; Vignarajan, Janardhan; An, Dong; Tay-Kearney, Mei-Ling; Kanagasingam, Yogi

    2016-03-01

    Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative assessment of retinal images is crucial in ocular diseases related clinical application. In this paper, we proposed approaches for improving the quality of blood vessel detection based on our initial blood vessel detection methods. A blood vessel spur pruning method has been developed for removing the blood vessel spurs both on vessel medial lines and binary vessel masks, which are caused by artifacts and side-effect of Gaussian matched vessel enhancement. A Gaussian matched filtering compensation method has been developed for removing incorrect vessel branches in the areas of low illumination. The proposed approaches were applied and tested on the color fundus images from one publicly available database and our diabetic retinopathy screening dataset. A preliminary result has demonstrated the robustness and good performance of the proposed approaches and their potential application for improving retinal blood vessel detection.

  14. Improved colour matching technique for fused nighttime imagery with daytime colours

    NASA Astrophysics Data System (ADS)

    Hogervorst, Maarten A.; Toet, Alexander

    2016-10-01

    Previously, we presented a method for applying daytime colours to fused nighttime (e.g., intensified and LWIR) imagery (Toet and Hogervorst, Opt.Eng. 51(1), 2012). Our colour mapping not only imparts a natural daylight appearance to multiband nighttime images but also enhances the contrast and visibility of otherwise obscured details. As a result, this colourizing method leads to increased ease of interpretation, better discrimination and identification of materials, faster reaction times and ultimately improved situational awareness (Toet e.a., Opt.Eng.53(4), 2014). A crucial step in this colouring process is the choice of a suitable colour mapping scheme. When daytime colour images and multiband sensor images of the same scene are available the colour mapping can be derived from matching image samples (i.e., by relating colour values to sensor signal intensities). When no exact matching reference images are available the colour transformation can be derived from the first-order statistical properties of the reference image and the multiband sensor image (Toet, Info. Fus. 4(3), 2003). In the current study we investigated new colour fusion schemes that combine the advantages of the both methods, using the correspondence between multiband sensor values and daytime colours (1st method) in a smooth transformation (2nd method). We designed and evaluated three new fusion schemes that focus on: i) a closer match with the daytime luminances, ii) improved saliency of hot targets and iii) improved discriminability of materials

  15. Dependability Improvement for PPM Compressed Data by Using Compression Pattern Matching

    NASA Astrophysics Data System (ADS)

    Kitakami, Masato; Okura, Toshihiro

    Data compression is popularly applied to computer systems and communication systems in order to reduce storage size and communication time, respectively. Since large data are used frequently, string matching for such data takes a long time. If the data are compressed, the time gets much longer because decompression is necessary. Long string matching time makes computer virus scan time longer and gives serious influence to the security of data. From this, CPM (Compression Pattern Matching) methods for several compression methods have been proposed. This paper proposes CPM method for PPM which achieves fast virus scan and improves dependability of the compressed data, where PPM is based on a Markov model, uses a context information, and achieves a better compression ratio than BW transform and Ziv-Lempel coding. The proposed method encodes the context information, which is generated in the compression process, and appends the encoded data at the beginning of the compressed data as a header. The proposed method uses only the header information. Computer simulation says that augmentation of the compression ratio is less than 5 percent if the order of the PPM is less than 5 and the source file size is more than 1M bytes, where order is the maximum length of the context used in PPM compression. String matching time is independent of the source file size and is very short, less than 0.3 micro seconds in the PC used for the simulation.

  16. Sport activities differentiating match-play improvement in elite youth footballers - a 2-year longitudinal study.

    PubMed

    Güllich, Arne; Kovar, Peter; Zart, Sebastian; Reimann, Ansgar

    2017-02-01

    This study examined contributions of different types of sport activities to the development of elite youth soccer performance. Match-play performance of 44 German male players was assessed by expert coaches twice, 24 months apart (age 11.1-13.1 years), based on videotaped 5v5 matches. Player pairs were matched by identical age and initial performance at t1. Each player was assigned to a group of either "Strong" or "Weak Responders" based on a higher or lower subsequent performance improvement at t2 within each pair (mean Δperformance 29% vs. 7%). A questionnaire recorded current and earlier amounts of organised practice/training and non-organised sporting play, in soccer and other sports, respectively. Group comparison revealed that "Strong Responders" accumulated more non-organised soccer play and organised practice/training in other sports, but not more organised soccer practice/training. Subsequent multivariate analyses (multiple linear regression analyses (MLR)) highlighted that higher resultant match-play performance at t2 was accounted for R(2)adj = 0.65 by performance at t1, together with more non-organised soccer play and organised engagement in other sports, respectively, and greater current, but less earlier volume of organised soccer. The findings suggest that variable early sporting experience facilitates subsequent soccer performance development in German elite youth footballers.

  17. Improving similarity-driven library design: customized matching and regioselective feature trees.

    PubMed

    Fischer, J Robert; Lessel, Uta; Rarey, Matthias

    2011-09-26

    Reduced graph descriptors, like feature trees, are frequently applied in cases where the relative arrangement of functional groups is more important than exact substructure matches. Due to their ability to deal with fragmented molecules, they are well-suited for fragment space search and library design. We recently presented LoFT, a novel focused library design approach based on feature trees. During evaluation two drawbacks of the reduced graph descriptor were discovered: First, regioisomeric substructures cannot be distinguished in feature tree mappings which results in a large information loss especially when connecting R-groups to cores. Second, the automatic matching procedure might result in undesired alignments, since the knowledge on what is considered as core by the user is not taken into account. In the following, we will present two approaches to overcome those drawbacks. The generation of the feature trees is modified, so that different arene substitution patterns can be recognized and a customized matching is introduced, allowing the user to determine the parts of the query, where the reagents are allowed to match. Subsequently we investigate the improvements on library design by reviewing the design scenarios which were already used for the evaluation of LoFT.

  18. Do quality improvement collaboratives' educational components match the dominant learning style preferences of the participants?

    PubMed

    Weggelaar-Jansen, Anne Marie; van Wijngaarden, Jeroen; Slaghuis, Sarah-Sue

    2015-06-20

    Quality improvement collaboratives are used to improve healthcare by various organizations. Despite their popularity literature shows mixed results on their effectiveness. A quality improvement collaborative can be seen as a temporary learning organization in which knowledge about improvement themes and methods is exchanged. In this research we studied: Does the learning approach of a quality improvement collaborative match the learning styles preferences of the individual participants and how does that affect the learning process of participants? This research used a mixed methods design combining a validated learning style questionnaire with data collected in the tradition of action research methodology to study two Dutch quality improvement collaboratives. The questionnaire is based on the learning style model of Ruijters and Simons, distinguishing five learning style preferences: Acquisition of knowledge, Apperception from others, Discovery of new insights, Exercising in fictitious situations and Participation with others. The most preferred learning styles of the participants were Discovery and Participation. The learning style Acquisition was moderately preferred and Apperception and Exercising were least preferred. The educational components of the quality improvement collaboratives studied (national conferences, half-day learning sessions, faculty site visits and use of an online tool) were predominantly associated with the learning styles Acquisition and Apperception. We observed a decrease in attendance to the learning activities and non-conformance with the standardized set goals and approaches. We conclude that the participants' satisfaction with the offered learning approach changed over time. The lacking match between these learning style preferences and the learning approach in the educational components of the quality improvement collaboratives studied might be the reason why the participants felt they did not gain new insights and therefore ceased

  19. Medical Student Mock Interviews to Improve Residency Interviewing and Match Success.

    PubMed

    Hueston, William J; Holloway, Richard L

    2016-04-01

    Using a quasi-experimental approach, we examined student and faculty satisfaction with a mock residency interview program. We also examined whether self-selected participants had match rates that differed from nonparticipants. Interviews were arranged on a specified evening between students and a physician in the specialty to which the student wished to apply. Interviews were structured as similarly to residency interviews as possible, but included 10 minutes of verbal feedback and subsequent written feedback to all students. Students completed surveys indicating their satisfaction with the mock interview immediately following the interview and 5 months later (after their actual resident interviews). Faculty feedback to students and their satisfaction with the program also was collected. Out of 189 (55%) students in the senior class, 104 volunteered to participate. Immediately following the mock interview, over 90% of students who participated either strongly agreed or agreed that the interview feedback was helpful, seemed realistic, and helped them identify strengths and weaknesses. Responses collected 5 months later were still favorable, but less positive. Faculty identified 7 students who they believed had poor interview techniques and an additional 13 who interviewers believed would be unlikely to match in their specialty. Final match results for the group participating in the mock interview showed a primary match rate of 99%, which was higher than students who did not participate (94%, P < .001). In a self-selected group of students who chose to participate, mock interviews were useful in improving student match success compared to students who did not participate in the mock interview program. Because all students were not required to participate, it is unclear whether this tactic would be successful for all students.

  20. Improved Electrical Load Match In California By Combining Solar Thermal Power Plants with Wind Farms

    SciTech Connect

    Vick, B. D.; Clark, R. N.; Mehos, M.

    2008-01-01

    will be during mid-day. Adding six hours of solar thermal storage improved the utility load match significantly in the evening and reliability was also improved. Storage improves reliability because electrical production can remain at a high level even when there are lulls in the wind or clouds decrease the solar energy striking the parabolic trough mirrors. The solar energy from Mojave Desert and wind energy in the major wind farm areas are not a good match to utility load during the winter in California, but if the number of wind farms were increased east of San Diego, then the utility renewable energy match would be improved (this is because the wind energy is highest during the winter in this area). Currently in California, wind electrical generation only contributes 1.8% of total electricity and solar electrical generation only contributes 0.2%. Combining wind farms and solar thermal power plants with storage would allow a large percentage of the electrical load in California to be met by wind and solar energy due to a better match with utility load than by either renewable resource separately.

  1. An improved tropospheric ozone database retrieved from SCIAMACHY Limb-Nadir-Matching method

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Rozanov, Alexei; Ladstätter-Weißenmayer, Annette; Ebojie, Felix; Rahpoe, Nabiz; Bötel, Stefan; Burrows, John

    2015-04-01

    Tropospheric ozone is one of the most important green-house gases and the main component of photochemical smog. It is either transported from the stratosphere or photochemically produced during pollution events in the troposphere that threaten the respiratory system. To investigate sources, transport mechanisms of tropospheric ozone in a global view, limb nadir matching (LNM) technique applied with SCIAMACHY instrument is used to retrieve tropospheric ozone. With the fact that 90% ozone is located in the stratosphere and only about 10% can be observed in the troposphere, the usage of satellite data requires highly qualified nadir and limb data. In this study we show an improvement of SCIAMACHY limb data as well as its influence on tropospheric ozone results. The limb nadir matching technique is also refined to increase the quality of the tropospheric ozone. The results are validated with ozone sonde measurements.

  2. Improvement of efficiency of piezoelectric element attached to beam based on mechanical impedance matching

    NASA Astrophysics Data System (ADS)

    Yamada, Keisuke; Matsuhisa, Hiroshi; Utsuno, Hideo

    2014-01-01

    This paper describes new methods that improve the efficiency of a piezoelectric element attached to a beam based on mechanical impedance matching. Piezoelectric elements are often used to suppress bending vibration. They are also used as sensors or energy-harvesting sources. In such cases, the piezoelectric element is usually bonded onto the host structure by an adhesive bond. The efficiency of the piezoelectric element depends on the bonding location. When the efficiency is insufficient despite a good location, the size or number of piezoelectric elements is increased. However, the efficiency of the piezoelectric element is usually insufficient even if these methods are applied. In order to enhance the efficiency of the piezoelectric elements without using active methods, this paper proposes a mechanical impedance matching method that uses spacers or tuning for the size of the piezoelectric element. Because the attached piezoelectric element and host structure in this region behave as springs in parallel to the bending deformation, the stored strain energy in the piezoelectric element is maximized under the condition that their spring constants match. The proposed methods were theoretically investigated with consideration for the effects of the bonding layer, spacers, and host structure. The optimum conditions for the proposed methods were theoretically formulated, and the effectiveness of the proposed methods and theoretical analysis was verified through simulations and experiments.

  3. Dispersive matched filtering of ultrasonic guided waves for improved sparse array damage localization

    NASA Astrophysics Data System (ADS)

    Luppescu, Gregory C.; Dawson, Alexander J.; Michaels, Jennifer E.

    2016-02-01

    Although bulk waves have served as the industry standard in nondestructive evaluation for many years, guided waves (Lamb waves in plates) have become the focus of many current research efforts because they are able to interrogate larger areas of a structure in less time. Despite this advantage, guided waves also have characteristics that obfuscate data interpretation. The first property of guided waves that complicates analysis is their dispersive nature: their wave speed is a function of frequency. The second is that they are multimodal: they propagate as multiple symmetric and antisymmetric modes. Using pulse-compression techniques and a priori calculations of theoretical dispersion curves, the dispersive matched filter attempts to take advantage of these otherwise undesirable characteristics by maximizing the autocorrelation for only one mode, ideally increasing both the signal-to-noise ratio and time-resolution of ultrasonic guided wave measurements. In this research, the responses from broadband chirp excitations are recorded from a sparse transducer array after propagation through an aluminum plate containing no damage and simulated damage. Dispersive matched filtering is applied to the measurements and localization images are generated using the delay-and-sum method. Imaging results are compared to those obtained with narrowband tone burst excitations in terms of their ability to detect and localize the different scatterers. Results show that the dispersive matched filter notably improves the quality of the localization images.

  4. Improved Topographic Models via Concurrent Airborne LIDAR and Dense Image Matching

    NASA Astrophysics Data System (ADS)

    Mandlburger, G.; Wenzel, K.; Spitzer, A.; Haala, N.; Glira, P.; Pfeifer, N.

    2017-09-01

    Modern airborne sensors integrate laser scanners and digital cameras for capturing topographic data at high spatial resolution. The capability of penetrating vegetation through small openings in the foliage and the high ranging precision in the cm range have made airborne LiDAR the prime terrain acquisition technique. In the recent years dense image matching evolved rapidly and outperforms laser scanning meanwhile in terms of the achievable spatial resolution of the derived surface models. In our contribution we analyze the inherent properties and review the typical processing chains of both acquisition techniques. In addition, we present potential synergies of jointly processing image and laser data with emphasis on sensor orientation and point cloud fusion for digital surface model derivation. Test data were concurrently acquired with the RIEGL LMS-Q1560 sensor over the city of Melk, Austria, in January 2016 and served as basis for testing innovative processing strategies. We demonstrate that (i) systematic effects in the resulting scanned and matched 3D point clouds can be minimized based on a hybrid orientation procedure, (ii) systematic differences of the individual point clouds are observable at penetrable, vegetated surfaces due to the different measurement principles, and (iii) improved digital surface models can be derived combining the higher density of the matching point cloud and the higher reliability of LiDAR point clouds, especially in the narrow alleys and courtyards of the study site, a medieval city.

  5. Improved frequency selective fat suppression in the posterior neck with tissue susceptibility matched pyrolytic graphite foam.

    PubMed

    Lee, Gary; Jordan, Caroline; Tiet, Pamela; Ruiz, Carlos; McCormick, Jeff; Phuong, Kevin; Hargreaves, Brian; Conolly, Steven

    2015-03-01

    To demonstrate improved frequency selective fat suppression in MRI using a magnetic susceptibility matching foam by reducing B0 inhomogeneities induced within the body by air-tissue interfaces. Flexible pyrolytic graphite (PG) composite foam was tailored to match the magnetic susceptibility of human tissue and was shaped to surround the cervical spine region. Field maps and frequency selective fat suppressed T1 -weighted FLASH images were acquired at 3 Tesla in both phantoms and six healthy necks. B0 field uniformity was shimmed to a target critical threshold of 1 ppm for fat suppression. The percentage of voxels in the phantom that did not achieve the critical threshold was reduced from 64% without the PG foam to only 1% with the foam. A similar decrease from 16% to 2% was observed in the in vivo region of interest. PG foam improved B0 field uniformity by moving air-tissue field gradients outside of the neck where they cannot cause MRI artifacts. The PG foams consistently mitigated signal dropout, improved overall SNR, and enabled more robust frequency selective fat suppression. © 2014 Wiley Periodicals, Inc.

  6. Improving mb:Ms discrimination using phase matched filters derived from regional group velocity tomography

    SciTech Connect

    Ford, S R; Hazler, S; Pasyanos, M E; Walter, W R

    1999-07-23

    This study reports on the ongoing investigation of surface wave group velocity dispersion across the Middle East and North Africa. Using broadband data gathered from various sources, we have measured group velocity using a multiple narrow-band filter method. To date, we have examined over 13,500 seismograms and made quality measurements for about 6500 Rayleigh and 3500 Love wave paths. A conjugate gradient method is used to perform the group velocity tomography at several periods. There is excellent agreement between short period structure and large known sedimentary features. Longer period structure is sensitive to crustal thickness, particularly the contrast between continental and oceanic regions and thicker crusts found beneath erogenic zones. We also find slow upper mantle velocities along rift systems. Correlation between the inversion results and known major tectonic features gives us confidence in our surface wave group velocities. Accurate group velocity maps can be used to construct phase matched filters. The filters can improve weak surface waves by compressing the dispersed signal. We are particularly interested in using the filters to calculate regionally determined M{sub s} measurements, which we hope can be used to extend the threshold of m{sub b}:M{sub s} discriminants to lower magnitude levels. A preliminary analysis of surface wave data processed using phase matched filters indicates a significant improvement in increasing the signal-to-noise ratio and improving magnitude estimates. Where signal-to-noise is very poor, phase matched filtering can still be useful in lowering the upper bound on M{sub s} measurements. We propose a series of tests in order to analyze the utility of phase matched filters. Goals of the study include determining at what distance and magnitude ranges we can expect to see improvement using the filters and the overall effect of the filters on discrimination capability. We also propose to look at seismic velocity models of

  7. Near perfect optics

    SciTech Connect

    Goeke, R.; Farnsworth, A.V.; Neumann, C.C.; Sweatt, W.C.; Warren, M.E.; Weed, J.W.

    1996-06-01

    This report discusses a novel fabrication process to produce nearly perfect optics. The process utilizes vacuum deposition techniques to optimally modify polished optical substrate surfaces. The surface figure, i.e. contour of a polished optical element, is improved by differentially filling in the low spots on the surface using flux from a physical vapor deposition source through an appropriate mask. The process is expected to enable the manufacture of diffraction-limited optical systems for the UV, extreme UV, and soft X-ray spectral regions, which would have great impact on photolithography and astronomy. This same technique may also reduce the fabrication cost of visible region optics with aspheric surfaces.

  8. Improving iris recognition performance using segmentation, quality enhancement, match score fusion, and indexing.

    PubMed

    Vatsa, Mayank; Singh, Richa; Noore, Afzel

    2008-08-01

    This paper proposes algorithms for iris segmentation, quality enhancement, match score fusion, and indexing to improve both the accuracy and the speed of iris recognition. A curve evolution approach is proposed to effectively segment a nonideal iris image using the modified Mumford-Shah functional. Different enhancement algorithms are concurrently applied on the segmented iris image to produce multiple enhanced versions of the iris image. A support-vector-machine-based learning algorithm selects locally enhanced regions from each globally enhanced image and combines these good-quality regions to create a single high-quality iris image. Two distinct features are extracted from the high-quality iris image. The global textural feature is extracted using the 1-D log polar Gabor transform, and the local topological feature is extracted using Euler numbers. An intelligent fusion algorithm combines the textural and topological matching scores to further improve the iris recognition performance and reduce the false rejection rate, whereas an indexing algorithm enables fast and accurate iris identification. The verification and identification performance of the proposed algorithms is validated and compared with other algorithms using the CASIA Version 3, ICE 2005, and UBIRIS iris databases.

  9. Automatic block-matching registration to improve lung tumor localization during image-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Robertson, Scott Patrick

    To improve relatively poor outcomes for locally-advanced lung cancer patients, many current efforts are dedicated to minimizing uncertainties in radiotherapy. This enables the isotoxic delivery of escalated tumor doses, leading to better local tumor control. The current dissertation specifically addresses inter-fractional uncertainties resulting from patient setup variability. An automatic block-matching registration (BMR) algorithm is implemented and evaluated for the purpose of directly localizing advanced-stage lung tumors during image-guided radiation therapy. In this algorithm, small image sub-volumes, termed "blocks", are automatically identified on the tumor surface in an initial planning computed tomography (CT) image. Each block is independently and automatically registered to daily images acquired immediately prior to each treatment fraction. To improve the accuracy and robustness of BMR, this algorithm incorporates multi-resolution pyramid registration, regularization with a median filter, and a new multiple-candidate-registrations technique. The result of block-matching is a sparse displacement vector field that models local tissue deformations near the tumor surface. The distribution of displacement vectors is aggregated to obtain the final tumor registration, corresponding to the treatment couch shift for patient setup correction. Compared to existing rigid and deformable registration algorithms, the final BMR algorithm significantly improves the overlap between target volumes from the planning CT and registered daily images. Furthermore, BMR results in the smallest treatment margins for the given study population. However, despite these improvements, large residual target localization errors were noted, indicating that purely rigid couch shifts cannot correct for all sources of inter-fractional variability. Further reductions in treatment uncertainties may require the combination of high-quality target localization and adaptive radiotherapy.

  10. Just Perfect, Part 2

    ERIC Educational Resources Information Center

    Scott, Paul

    2007-01-01

    In "Just Perfect: Part 1," the author defined a perfect number N to be one for which the sum of the divisors d (1 less than or equal to d less than N) is N. He gave the first few perfect numbers, starting with those known by the early Greeks. In this article, the author provides an extended list of perfect numbers, with some comments about their…

  11. [Improving hyperspectral matching method through feature-selection/weighting based on SVM].

    PubMed

    Wang, Yuan-Yuan; Chen, Yun-Hao; Li, Jing

    2009-03-01

    In the present article, feature selection/weighting based on SVM was employed to improve the algorithm of choosing reference spectrum through a multi-objective optimization approach proposed in reference. Based on the sensitive analysis, half of features having low weights in SVM classification model were eliminated iteratively. Two criteria, matching accuracy and classification confidence, were used to select the best-performing feature subset. Three scenarios were designed: (1) only feature subset selected by SVM was used; (2) both feature subset and global weights were used, in which global weights were the coefficients of selected features in the SVM classification model; (3) both feature subset and local weights, which changed with the distance of a sample point to the SVM separation plan, were used. Experiment executed on the popular Indiana AVIRIS data set indicate that under all the three scenarios, spectral matching accuracies were increased by 13%-17% compared to the situation without feature selection. The result obtained under scenario 3 is the most accurate and the most stable, which can be primarily attributed to the ability of local weights to accurately describe local distribution of spectra from the same class in feature space. Moreover, scenario 3 can be regarded as the extension of scenario 2 because when spectra far away from the separation plane are selected as reference spectrums for matching, the features' weights will not be considered. The results obtained under scenario 1 and 2 are very similar, indicating that considering global weights is not necessary. The research presented in this paper advanced the spectrum analysis using SVM to a higher level.

  12. Astronomical image denoising by means of improved adaptive backtracking-based matching pursuit algorithm.

    PubMed

    Liu, Qianshun; Bai, Jian; Yu, Feihong

    2014-11-10

    In an effort to improve compressive sensing and spare signal reconstruction by way of the backtracking-based adaptive orthogonal matching pursuit (BAOMP), a new sparse coding algorithm called improved adaptive backtracking-based OMP (ABOMP) is proposed in this study. Many aspects have been improved compared to the original BAOMP method, including replacing the fixed threshold with an adaptive one, adding residual feedback and support set verification, and others. Because of these ameliorations, the proposed algorithm can more precisely choose the atoms. By adding the adaptive step-size mechanism, it requires much less iteration and thus executes more efficiently. Additionally, a simple but effective contrast enhancement method is also adopted to further improve the denoising results and visual effect. By combining the IABOMP algorithm with the state-of-art dictionary learning algorithm K-SVD, the proposed algorithm achieves better denoising effects for astronomical images. Numerous experimental results show that the proposed algorithm performs successfully and effectively on Gaussian and Poisson noise removal.

  13. Fingerprint identification using SIFT-based minutia descriptors and improved all descriptor-pair matching.

    PubMed

    Zhou, Ru; Zhong, Dexing; Han, Jiuqiang

    2013-03-06

    The performance of conventional minutiae-based fingerprint authentication algorithms degrades significantly when dealing with low quality fingerprints with lots of cuts or scratches. A similar degradation of the minutiae-based algorithms is observed when small overlapping areas appear because of the quite narrow width of the sensors. Based on the detection of minutiae, Scale Invariant Feature Transformation (SIFT) descriptors are employed to fulfill verification tasks in the above difficult scenarios. However, the original SIFT algorithm is not suitable for fingerprint because of: (1) the similar patterns of parallel ridges; and (2) high computational resource consumption. To enhance the efficiency and effectiveness of the algorithm for fingerprint verification, we propose a SIFT-based Minutia Descriptor (SMD) to improve the SIFT algorithm through image processing, descriptor extraction and matcher. A two-step fast matcher, named improved All Descriptor-Pair Matching (iADM), is also proposed to implement the 1:N verifications in real-time. Fingerprint Identification using SMD and iADM (FISiA) achieved a significant improvement with respect to accuracy in representative databases compared with the conventional minutiae-based method. The speed of FISiA also can meet real-time requirements.

  14. An Improved Algorithm of Congruent Matching Cells (CMC) Method for Firearm Evidence Identifications

    PubMed Central

    Tong, Mingsi; Song, John; Chu, Wei

    2015-01-01

    The Congruent Matching Cells (CMC) method was invented at the National Institute of Standards and Technology (NIST) for firearm evidence identifications. The CMC method divides the measured image of a surface area, such as a breech face impression from a fired cartridge case, into small correlation cells and uses four identification parameters to identify correlated cell pairs originating from the same firearm. The CMC method was validated by identification tests using both 3D topography images and optical images captured from breech face impressions of 40 cartridge cases fired from a pistol with 10 consecutively manufactured slides. In this paper, we discuss the processing of the cell correlations and propose an improved algorithm of the CMC method which takes advantage of the cell correlations at a common initial phase angle and combines the forward and backward correlations to improve the identification capability. The improved algorithm is tested by 780 pairwise correlations using the same optical images and 3D topography images as the initial validation. PMID:26958441

  15. Fingerprint Identification Using SIFT-Based Minutia Descriptors and Improved All Descriptor-Pair Matching

    PubMed Central

    Zhou, Ru; Zhong, Dexing; Han, Jiuqiang

    2013-01-01

    The performance of conventional minutiae-based fingerprint authentication algorithms degrades significantly when dealing with low quality fingerprints with lots of cuts or scratches. A similar degradation of the minutiae-based algorithms is observed when small overlapping areas appear because of the quite narrow width of the sensors. Based on the detection of minutiae, Scale Invariant Feature Transformation (SIFT) descriptors are employed to fulfill verification tasks in the above difficult scenarios. However, the original SIFT algorithm is not suitable for fingerprint because of: (1) the similar patterns of parallel ridges; and (2) high computational resource consumption. To enhance the efficiency and effectiveness of the algorithm for fingerprint verification, we propose a SIFT-based Minutia Descriptor (SMD) to improve the SIFT algorithm through image processing, descriptor extraction and matcher. A two-step fast matcher, named improved All Descriptor-Pair Matching (iADM), is also proposed to implement the 1:N verifications in real-time. Fingerprint Identification using SMD and iADM (FISiA) achieved a significant improvement with respect to accuracy in representative databases compared with the conventional minutiae-based method. The speed of FISiA also can meet real-time requirements. PMID:23467056

  16. Improving acoustic streaming effects in fluidic systems by matching SU-8 and polydimethylsiloxane layers.

    PubMed

    Catarino, S O; Minas, G; Miranda, J M

    2016-07-01

    This paper reports the use of acoustic waves for promoting and improving streaming in tridimensional polymethylmethacrylate (PMMA) cuvettes of 15mm width×14mm height×2.5mm thickness. The acoustic waves are generated by a 28μm thick poly(vinylidene fluoride) - PVDF - piezoelectric transducer in its β phase, actuated at its resonance frequency: 40MHz. The acoustic transmission properties of two materials - SU-8 and polydimethylsiloxane (PDMS) - were numerically compared. It was concluded that PDMS inhibits, while SU-8 allows, the transmission of the acoustic waves to the propagation medium. Therefore, by simulating the acoustic transmission properties of different materials, it is possible to preview the acoustic behavior in the fluidic system, which allows the optimization of the best layout design, saving costs and time. This work also presents a comparison between numerical and experimental results of acoustic streaming obtained with that β-PVDF transducer in the movement and in the formation of fluid recirculation in tridimensional closed domains. Differences between the numerical and experimental results are credited to the high sensitivity of acoustic streaming to the experimental conditions and to limitations of the numerical method. The reported study contributes for the improvement of simulation models that can be extremely useful for predicting the acoustic effects of new materials in fluidic devices, as well as for optimizing the transducers and matching layers positioning in a fluidic structure. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. An Improved Map-Matching Technique Based on the Fréchet Distance Approach for Pedestrian Navigation Services

    PubMed Central

    Bang, Yoonsik; Kim, Jiyoung; Yu, Kiyun

    2016-01-01

    Wearable and smartphone technology innovations have propelled the growth of Pedestrian Navigation Services (PNS). PNS need a map-matching process to project a user’s locations onto maps. Many map-matching techniques have been developed for vehicle navigation services. These techniques are inappropriate for PNS because pedestrians move, stop, and turn in different ways compared to vehicles. In addition, the base map data for pedestrians are more complicated than for vehicles. This article proposes a new map-matching method for locating Global Positioning System (GPS) trajectories of pedestrians onto road network datasets. The theory underlying this approach is based on the Fréchet distance, one of the measures of geometric similarity between two curves. The Fréchet distance approach can provide reasonable matching results because two linear trajectories are parameterized with the time variable. Then we improved the method to be adaptive to the positional error of the GPS signal. We used an adaptation coefficient to adjust the search range for every input signal, based on the assumption of auto-correlation between consecutive GPS points. To reduce errors in matching, the reliability index was evaluated in real time for each match. To test the proposed map-matching method, we applied it to GPS trajectories of pedestrians and the road network data. We then assessed the performance by comparing the results with reference datasets. Our proposed method performed better with test data when compared to a conventional map-matching technique for vehicles. PMID:27782091

  18. Making a Good Match: How Schools and External Service Providers Negotiate Needs and Services in Support of School Improvement

    ERIC Educational Resources Information Center

    Vixie Sandy, Mary

    2013-01-01

    This study investigated a problem facing policy makers, education leaders, and external providers of service that support or facilitate school-based change designed to improve teaching and learning: How to match school needs with providers' services in ways that maximize school improvement. A growing number of organizations provide service to…

  19. Jeffries Matusita based mixed-measure for improved spectral matching in hyperspectral image analysis

    NASA Astrophysics Data System (ADS)

    Padma, S.; Sanjeevi, S.

    2014-10-01

    This paper proposes a novel hyperspectral matching technique by integrating the Jeffries-Matusita measure (JM) and the Spectral Angle Mapper (SAM) algorithm. The deterministic Spectral Angle Mapper and stochastic Jeffries-Matusita measure are orthogonally projected using the sine and tangent functions to increase their spectral ability. The developed JM-SAM algorithm is implemented in effectively discriminating the landcover classes and cover types in the hyperspectral images acquired by PROBA/CHRIS and EO-1 Hyperion sensors. The reference spectra for different land-cover classes were derived from each of these images. The performance of the proposed measure is compared with the performance of the individual SAM and JM approaches. From the values of the relative spectral discriminatory probability (RSDPB) and relative discriminatory entropy value (RSDE), it is inferred that the hybrid JM-SAM approach results in a high spectral discriminability than the SAM and JM measures. Besides, the use of the improved JM-SAM algorithm for supervised classification of the images results in 92.9% and 91.47% accuracy compared to 73.13%, 79.41%, and 85.69% of minimum-distance, SAM and JM measures. It is also inferred that the increased spectral discriminability of JM-SAM measure is contributed by the JM distance. Further, it is seen that the proposed JM-SAM measure is compatible with varying spectral resolutions of PROBA/CHRIS (62 bands) and Hyperion (242 bands).

  20. Improved obstetrical outcomes for adolescents in a community-based outreach program: a matched cohort study.

    PubMed

    Fleming, Nathalie A; Tu, Xiaowen; Black, Amanda Y

    2012-12-01

    Adolescent pregnancies are higher-risk pregnancies, and standard obstetrical care environments may not meet their needs. The objective of this study was to determine if adolescents followed in a community-based adolescent outreach obstetrical program had improved perinatal outcomes compared with provincial control subjects. We conducted a matched cohort study. Adolescent women who received prenatal care in the outreach program between 2004 and 2010 (intervention group, n = 206) were identified and matched 1:4 to adolescent control subjects in the provincial perinatal database (n = 831). Chi-square and Student t tests were performed for categorical and continuous variables. Regression models assessed the association between the intervention and pregnancy/perinatal outcomes. The intervention cohort had significantly higher rates of smoking, drug use, and alcohol use than control subjects P < 0.001); however, rates of first trimester visits (76.7% vs. 64%, P = 0.009), prenatal class attendance (52.8% vs. 30.3%; P < 0.001), and group B streptococcus screening (P = 0.01) were also higher. Although the intervention cohort had higher risk behaviours than control subjects, there were no significant differences between the groups in the proportion of preterm or very preterm births, low birth weight or very low birth weight infants, or intrauterine growth restricted/small for gestational age infants. The intervention cohort had a significantly higher mean gestational age at delivery (P = 0.005) and higher mean birth weight (P = 0.002) than control subjects. The adjusted relative risk of low birth weight was significantly lower in the intervention group (RR 0.41; 95% CI 0.18 to 0.95) and a decreased risk of preterm delivery was seen (RR 0.47; 95% CI 0.22 to 1.00). Pregnant adolescents may engage in higher-risk behaviours that can affect perinatal outcomes. Early prenatal care and education in adolescent-friendly programs may mitigate the effect of these behaviours on

  1. Never Perfect Enough

    ERIC Educational Resources Information Center

    Landphair, Juliette

    2007-01-01

    What exactly is perfect? Students describe perfection as a combination of characteristics valued by their peer culture: intelligence, thin and fit physical appearance, social poise. As students chug through their daily lives--morning classes, organization meetings, club sports practice or the gym, dinner, another class, more meetings, library,…

  2. Never Perfect Enough

    ERIC Educational Resources Information Center

    Landphair, Juliette

    2007-01-01

    What exactly is perfect? Students describe perfection as a combination of characteristics valued by their peer culture: intelligence, thin and fit physical appearance, social poise. As students chug through their daily lives--morning classes, organization meetings, club sports practice or the gym, dinner, another class, more meetings, library,…

  3. Perfect embezzlement of entanglement

    NASA Astrophysics Data System (ADS)

    Cleve, Richard; Liu, Li; Paulsen, Vern I.

    2017-01-01

    Van Dam and Hayden introduced a concept commonly referred to as embezzlement, where, for any entangled quantum state ϕ, there is an entangled catalyst state ψ, from which a high fidelity approximation of ϕ ⊗ ψ can be produced using only local operations. We investigate a version of this where the embezzlement is perfect (i.e., the fidelity is 1). We prove that perfect embezzlement is impossible in a tensor product framework, even with infinite-dimensional Hilbert spaces and infinite entanglement entropy. Then we prove that perfect embezzlement is possible in a commuting operator framework. We prove this using the theory of C*-algebras and we also provide an explicit construction. Next, we apply our results to analyze perfect versions of a nonlocal game introduced by Regev and Vidick. Finally, we analyze the structure of perfect embezzlement protocols in the commuting operator model, showing that they require infinite-dimensional Hilbert spaces.

  4. SU-E-T-622: Identification and Improvement of Patients Eligible for Dose Escalation with Matched Plans

    SciTech Connect

    Bush, K; Holcombe, C; Kapp, D; Buyyounouski, M; Hancock, S; Xing, L; Atwood, T; King, M

    2014-06-15

    Purpose: Radiation-therapy dose-escalation beyond 80Gy may improve tumor control rates for patients with localized prostate cancer. Since toxicity remains a concern, treatment planners must achieve dose-escalation while still adhering to dose-constraints for surrounding structures. Patientmatching is a machine-learning technique that identifies prior patients that dosimetrically match DVH parameters of target volumes and critical structures prior to actual treatment planning. We evaluated the feasibility of patient-matching in (1)identifying candidates for safe dose-escalation; and (2)improving DVH parameters for critical structures in actual dose-escalated plans. Methods: We analyzed DVH parameters from 319 historical treatment plans to determine which plans could achieve dose-escalation (8640cGy) without exceeding Zelefsky dose-constraints (rectal and bladder V47Gy<53%, and V75.6Gy<30%, max-point dose to rectum of 8550cGy, max dose to PTV< 9504cGy). We then estimated the percentage of cases that could achieve safe dose-escalation using software that enables patient matching (QuickMatch, Siris Medical, Mountain View, CA). We then replanned a case that had violated DVH constraints with DVH parameters from patient matching, in order to determine whether this previously unacceptable plan could be made eligible with this automated technique. Results: Patient-matching improved the percentage of patients eligible for dose-escalation from 40% to 63% (p=4.7e-4, t-test). Using a commercial optimizer augmented with patient-matching, we demonstrated a case where patient-matching improved the toxicity-profile such that dose-escalation would have been possible; this plan was rapidly achieved using patientmatching software. In this patient, all lower-dose constraints were met with both the denovo and patient-matching plan. In the patient-matching plan, maximum dose to the rectum was 8385cGy, while the denovo plan failed to meet the maximum rectal constraint at 8571c

  5. An improved earthquake catalogue in the Marmara Sea region, Turkey, using massive template matching

    NASA Astrophysics Data System (ADS)

    Matrullo, Emanuela; Lengliné, Olivier; Schmittbuhl, Jean; Karabulut, Hayrullah; Bouchon, Michel

    2016-04-01

    After the 1999 Izmit earthquake, the Main Marmara Fault (MMF) represents a 150 km unruptured segment of the North Anatolian Fault located below the Marmara Sea. One of the principal issue for seismic hazard assessment in the region is to know if the MMF is totally or partially locked and where the nucleation of the major forthcoming event is going to take place. The area is actually one of the best-instrumented fault systems in Europe. Since year 2007, various seismic networks both broadband, short period and OBS stations were deployed in order to monitor continuously the seismicity along the MMF and the related fault systems. A recent analysis of the seismicity recorded during the 2007-2012 period has provided new insights on the recent evolution of this important regional seismic gap. This analysis was based on events detected with STA/LTA procedure and manually picked P and S wave arrivals times (Schmittbuhl et al., 2015). In order to extend the level of details and to fully take advantage of the dense seismic network we improved the seismic catalog using an automatic earthquake detection technique based on a template matching approach. This approach uses known earthquake seismic signals in order to detect newer events similar to the tested one from waveform cross-correlation. To set-up the methodology and verify the accuracy and the robustness of the results, we initially focused in the eastern part of the Marmara Sea (Cinarcik basin) and compared new detection with those manually identified. Through the massive analysis of cross-correlation based on the template scanning of the continuous recordings, we construct a refined catalog of earthquakes for the Marmara Sea in 2007-2014 period. Our improved earthquake catalog will provide an effective tool to improve the catalog completeness, to monitor and study the fine details of the time-space distribution of events, to characterize the repeating earthquake source processes and to understand the mechanical state of

  6. Improved perfect-fluid energy-momentum tensor with spin in Einstein-Cartan space-time. [applicable to problems in cosmology

    NASA Technical Reports Server (NTRS)

    Ray, J. R.; Smalley, L. L.

    1982-01-01

    The description of the spin given here is classical in that it is intrinsic but not quantized. The approach in this matter is similar to, for example, the work of Bailey and Israel (1973, 1975, 1979), where the fluid particles, which have intrinsic spin, may be galaxies or clusters of galaxies. The elementary particles of these objects and the 'ferromagnetic alignment' of their quantum spins are not resorted to in order to describe a fluid with spin. Physically this means that the equation of motion for the spin tensor is a modified Fermi-Walker transport equation (Misner et al., 1973), arising as a direct result of the inclusion of spin as an intrinsic variable in the thermodynamic description of the internal energy. The variables in this description are classical variables throughout and are not microscopic fields. An improved perfect-fluid energy-momentum tensor that includes spin and torsion is presented. Use is made of a Lagrangian variational principle based on the tetrad formalism of Halbwach (1960) and the method od constraints of Ray (1972).

  7. Changes in Patient Sorting to Nursing Homes under Public Reporting: Improved Patient Matching or Provider Gaming?

    PubMed Central

    Werner, Rachel M; Konetzka, R Tamara; Stuart, Elizabeth A; Polsky, Daniel

    2011-01-01

    Objective To test whether public reporting in the setting of postacute care in nursing homes results in changes in patient sorting. Data Sources/Study Setting All postacute care admissions from 2001 to 2003 in the nursing home Minimum Data Set. Study Design We test changes in patient sorting (or the changes in the illness severity of patients going to high- versus low-scoring facilities) when public reporting was initiated in nursing homes in 2002. We test for changes in sorting with respect to pain, delirium, and walking and then examine the potential roles of cream skimming and downcoding in changes in patient sorting. We use a difference-in-differences framework, taking advantage of the variation in the launch of public reporting in pilot and nonpilot states, to control for underlying trends in patient sorting. Principal Findings There was a significant change in patient sorting with respect to pain after public reporting was initiated, with high-risk patients being more likely to go to high-scoring facilities and low-risk patients more likely to go to low-scoring facilities. There was also an overall decrease in patient risk of pain with the launch of public reporting, which may be consistent with changes in documentation of pain levels (or downcoding). There was no significant change in sorting for delirium or walking. Conclusions Public reporting of nursing home quality improves matching of high-risk patients to high-quality facilities. However, efforts should be made to reduce the incentives for downcoding by nursing facilities. PMID:21105869

  8. Improved ventilation-perfusion matching by abdominal insufflation (pneumoperitoneum) with CO2 but not with air.

    PubMed

    Strang, C M; Ebmeyer, U; Maripuu, E; Hachenberg, T; Hedenstierna, G

    2013-06-01

    Pneumoperitoneum (PP) by CO2-insufflation causes atelectasis however with maintained or even improved oxygenation. We studied the effect of abdominal insufflation by carbon dioxide (CO2) and air on gas exchange during PP. Twenty-seven anesthetized pigs were studied during PP with insufflations to 12 mmHg by either 1/CO2, 2/ air or 3/CO2 during intravenous nitroprusside infusion (SNP) (N.=9 in each group). In 3 pigs in each group, gamma camera technique (SPECT) was used to study ventilation and perfusion distributions, in another 6 pigs an inert-gas technique (MIGET) was used for assessing ventilation-perfusion matching (VA/Q). Measurements were made during anesthesia before and after 60 minutes of PP. CO2-PP caused a shift of blood flow away from dependent, non-ventilated (atelectatic) to ventilated regions. Air-PP caused smaller, and SNP-PP even less shift of lung blood flow. Shunt decreased during CO2-PP (6 ± 1% compared to baseline 9 ± 2%, P<0.05), did not change during Air-PP (10 ± 2%) and increased during SNP-PP (16 ± 2%, P<0.05). PaO2 increased from baseline 35 ± 2 to 41 ± 3 kPa during CO2-PP and decreased to 32 ± 3 kPa during Air-PP and to 27 ± 3 kPa during SNP-PP (P<0.05 for all three comparisons). PaCO2 increased during CO2- and SNP-PP. CO2-PP enhanced the shift of blood flow towards better ventilated areas of the lung compared to Air-PP and SNP blunted the effects seen with CO2-PP. SNP may thus have blunted and CO2 potentiated vasoconstriction, by hypoxic pulmonary vasoconstriction or another mechanism.

  9. Combining machine learning and matching techniques to improve causal inference in program evaluation.

    PubMed

    Linden, Ariel; Yarnold, Paul R

    2016-12-01

    Program evaluations often utilize various matching approaches to emulate the randomization process for group assignment in experimental studies. Typically, the matching strategy is implemented, and then covariate balance is assessed before estimating treatment effects. This paper introduces a novel analytic framework utilizing a machine learning algorithm called optimal discriminant analysis (ODA) for assessing covariate balance and estimating treatment effects, once the matching strategy has been implemented. This framework holds several key advantages over the conventional approach: application to any variable metric and number of groups; insensitivity to skewed data or outliers; and use of accuracy measures applicable to all prognostic analyses. Moreover, ODA accepts analytic weights, thereby extending the methodology to any study design where weights are used for covariate adjustment or more precise (differential) outcome measurement. One-to-one matching on the propensity score was used as the matching strategy. Covariate balance was assessed using standardized difference in means (conventional approach) and measures of classification accuracy (ODA). Treatment effects were estimated using ordinary least squares regression and ODA. Using empirical data, ODA produced results highly consistent with those obtained via the conventional methodology for assessing covariate balance and estimating treatment effects. When ODA is combined with matching techniques within a treatment effects framework, the results are consistent with conventional approaches. However, given that it provides additional dimensions and robustness to the analysis versus what can currently be achieved using conventional approaches, ODA offers an appealing alternative. © 2016 John Wiley & Sons, Ltd.

  10. Just Perfect: Part 1

    ERIC Educational Resources Information Center

    Scott, Paul

    2007-01-01

    This article is about a very small subset of the positive integers. The positive integer N is said to be "perfect" if it is the sum of all its divisors, including 1, but less that N itself. For example, N = 6 is perfect, because the (relevant) divisors are 1, 2 and 3, and 6 = 1 + 2 + 3. On the other hand, N = 12 has divisors 1, 2, 3, 4 and 6, but…

  11. Improved electrical load match in California by combining solar thermal power plants with wind farms

    USDA-ARS?s Scientific Manuscript database

    The ability of wind and solar electrical energy generation to match the current utility electrical load in California was analyzed. We compared the renewable electrical generation and the utility load in California using actual hourly wind farm data at two different locations and predicted hourly p...

  12. Misleading Cues Improve Developmental Assessment of Working Memory Capacity: The Color Matching Tasks

    ERIC Educational Resources Information Center

    Arsalidou, Marie; Pascual-Leone, Juan; Johnson, Janice

    2010-01-01

    The theory of constructive operators was used as a framework to design two versions of a paradigm (color matching task, CMT) in which items are parametrically ordered in difficulty, and differ only contextually. Items in CMT-Balloon are facilitating, whereas items in CMT-Clown contain misleading cues. Participants of ages 7-14 years and adults (N…

  13. Misleading Cues Improve Developmental Assessment of Working Memory Capacity: The Color Matching Tasks

    ERIC Educational Resources Information Center

    Arsalidou, Marie; Pascual-Leone, Juan; Johnson, Janice

    2010-01-01

    The theory of constructive operators was used as a framework to design two versions of a paradigm (color matching task, CMT) in which items are parametrically ordered in difficulty, and differ only contextually. Items in CMT-Balloon are facilitating, whereas items in CMT-Clown contain misleading cues. Participants of ages 7-14 years and adults (N…

  14. Caffeine-containing energy drink improves physical performance of elite rugby players during a simulated match.

    PubMed

    Del Coso, Juan; Ramírez, Juan A; Muñoz, Gloria; Portillo, Javier; Gonzalez-Millán, Cristina; Muñoz, Víctor; Barbero-Álvarez, José C; Muñoz-Guerra, Jesús

    2013-04-01

    The purpose of this study was to investigate the effectiveness of a caffeine-containing energy drink in enhancing rugby players' physical performance during a simulated match. A second purpose was to determine the urinary caffeine excretion derived from the energy drink intake. In a randomized and counterbalanced order, 26 elite rugby players (mean ± SD for age and body mass, 25 ± 2 y and 93 ± 15 kg) played 2 simulated rugby games (2 × 30 min) 60 min after ingesting (i) 3 mg of caffeine per kilogram of body mass in the form of an energy drink (Fure, ProEnergetics) or (ii) the same drink without caffeine (placebo). During the matches, the individual running distance and the instantaneous speed were measured, and the number of running actions above 20 km·h(-1) (i.e., sprints) were determined, using global positioning system devices. The number of impacts above 5 g during the matches was determined by accelerometry. The ingestion of the energy drink, compared with the placebo, increased the total distance covered during the match (4749 ± 589 vs 5139 ± 475 m, p < 0.05), the running distance covered at more than 20 km·h(-1) (184 ± 38 vs 208 ± 38 m, p < 0.05), and the number of sprints (10 ± 7 vs 12 ± 7, p < 0.05). The ingestion of the energy drink also resulted in a greater overall number of impacts (481 ± 352 vs 641 ± 366, p < 0.05) and a higher postexercise urine caffeine concentration (0.1 ± 0.1 vs 2.4 ± 0.9 μg·mL(-1), p < 0.05). The use of an energy drink with a caffeine dose equivalent to 3 mg·kg(-1) considerably enhanced the movement patterns of rugby players during a simulated match.

  15. Can metric-based approaches really improve multi-model climate projections? A perfect model framework applied to summer temperature change in France.

    NASA Astrophysics Data System (ADS)

    Boé, Julien; Terray, Laurent

    2014-05-01

    -based approach a posterior estimate of climate change, based on the synthetic observation of the metric. Finally, it is possible to compare the posterior estimate to the synthetic observation of future climate change to evaluate the skill of the method. The main objective of this presentation is to describe and apply this perfect model framework to test different methodological issues associated with non-uniform model weighting and similar metric-based approaches. The methodology presented is general, but will be applied to the specific case of summer temperature change in France, for which previous works have suggested potentially useful metrics associated with soil-atmosphere and cloud-temperature interactions. The relative performances of different simple statistical approaches to combine multiple model results based on metrics will be tested. The impact of ensemble size, observational errors, internal variability, and model similarity will be characterized. The potential improvements associated with metric-based approaches compared to the MMEM is terms of errors and uncertainties will be quantified.

  16. Oxytocin does not improve performance of patients with schizophrenia and healthy volunteers in a facial emotion matching task.

    PubMed

    Horta de Macedo, Ligia R; Zuardi, Antonio Waldo; Machado-de-Sousa, João Paulo; Chagas, Marcos Hortes N; Hallak, Jaime E C

    2014-12-15

    The neuropeptide oxytocin improves the performance in facial emotion recognition tests in healthy volunteers and in individuals with schizophrenia. Different paradigms are used in emotion recognition tasks, engaging different neurobiological bases. To date, the effects of oxytocin in facial emotion matching tasks have not been studied. The objective of this study was to evaluate the effects of intranasal oxytocin in a facial emotion matching task in patients with schizophrenia and healthy volunteers. Twenty patients and 20 healthy volunteers received 48 IU intranasal oxytocin and placebo in a double-blind, randomized, placebo-controlled, within subjects design. Fifty minutes after treatment, subjects completed a facial emotion matching task and three control tests. Oxytocin failed to improve facial affect processing, in contrast with previous results. Possible explanations are the fact that we used a facial emotion matching paradigm instead of emotion labeling tasks and a higher dose of oxytocin than the one used in most similar studies. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. Adding Boolean-Quality Control to Best-Match Searching via an Improved User Interface

    DTIC Science & Technology

    2000-05-01

    librarians and others—preferred Boolean systems by a wide margin. For example, commercial services like Westlaw , DIALOG, and Lexis/Nexis began offering a...exact-match evaluation. In mid-1999, Joanne Claussen of Westlaw said of their service (Claussen 1999): “The usage of Boolean versus natural language...Joanne Claussen of Westlaw and Daniel Pliske of Lexis/Nexis provided information on Boolean versus natural language usage of their respective services

  18. An improved implementation of block matching for motion estimation in ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Cardoso, Fernando M.; Furuie, Sergio S.

    2017-03-01

    Ultrasound elastography has become an important procedure that provides information about the tissue dynamics and may help on the detection of tissue abnormalities. Therefore, motion estimation in a sequence of ultrasound acquisition is crucial to the quality of this information. We propose a novel algorithm to perform speckle tracking, which consists in an implementation of 2D Block Matching with two enhancements: sub-pixel linear interpolation and displacement propagation, which are able to increase resolution, reduce computation time and prevent kernel mismatching errors. This method does not require any additional hardware and provide real-time information. The proposed technique was evaluated using four different numerical phantoms and its results were compared with the results from standard 2D block matching and optical flow. The proposed method outperformed the other two methods, providing an average error of 0.98 pixels, while standard 2D block matching and optical flow presented an average error of 2.50 and 10.03 pixels, respectively. The proposed algorithm was also assessed with four different physical phantoms and a qualitative comparison showed that the proposed technique presented results that were compatible to the results from the built-in elastography mode of the ultrasound equipment (Ultrasonix Touch).

  19. Matrix-Matching as an Improvement Strategy for the Detection of Pesticide Residues.

    PubMed

    Giacinti, Géraldine; Raynaud, Christine; Capblancq, Sophie; Simon, Valérie

    2016-05-01

    More than 90% of the pesticides residues in apples are located in the peel. We developed a gas chromatography/ion trap tandem mass spectrometry method for investigating all detectable residues in the peel of 3 apple varieties. Sample preparation is based on the use of the Quick Easy Cheap Effective Rugged and Safe method on the whole fruit, the flesh, and the peel. Pesticide residues were quantified with solvent-matched and matrix-matched standards, by spiking apple sample extracts. Matrix effects dependent on the type of extract (fruit, flesh, or peel) and the apple variety were detected. The best data processing methods involved normalizing matrix effect rates by matrix-matched internal/external calibration. Boscalid, captan, chlorpyrifos, fludioxonil, and pyraclostrobin were the most frequently detected pesticides. However, their concentrations in the whole fruit were below European maximum residue levels. Despite negative matrix effects, the residues in peel were detected at concentrations up to 10 times higher than those in whole fruits. Consequently, other pesticide residues present at concentrations below the limit of quantification in the whole fruit were detected in the peel. © 2016 Institute of Food Technologists®

  20. Invariant perfect tensors

    NASA Astrophysics Data System (ADS)

    Li, Youning; Han, Muxin; Grassl, Markus; Zeng, Bei

    2017-06-01

    Invariant tensors are states in the SU(2) tensor product representation that are invariant under SU(2) action. They play an important role in the study of loop quantum gravity. On the other hand, perfect tensors are highly entangled many-body quantum states with local density matrices maximally mixed. Recently, the notion of perfect tensors has attracted a lot of attention in the fields of quantum information theory, condensed matter theory, and quantum gravity. In this work, we introduce the concept of an invariant perfect tensor (IPT), which is an n-valent tensor that is both invariant and perfect. We discuss the existence and construction of IPTs. For bivalent tensors, the IPT is the unique singlet state for each local dimension. The trivalent IPT also exists and is uniquely given by Wigner’s 3j symbol. However, we show that, surprisingly, 4-valent IPTs do not exist for any identical local dimension d. On the contrary, when the dimension is large, almost all invariant tensors are asymptotically perfect, which is a consequence of the phenomenon of the concentration of measure for multipartite quantum states.

  1. Improving Students' Understanding of the Connections between the Concepts of Real-Gas Mixtures, Gas Ideal-Solutions, and Perfect-Gas Mixtures

    ERIC Educational Resources Information Center

    Privat, Romain; Jaubert, Jean-Noël; Moine, Edouard

    2016-01-01

    In many textbooks of chemical-engineering thermodynamics, a gas mixture obeying the fundamental law pV[subscript m] = RT is most often called ideal-gas mixture (in some rare cases, the term perfect-gas mixture can be found). These textbooks also define the fundamental concept of ideal solution which in theory, can be applied indifferently to…

  2. Improving Students' Understanding of the Connections between the Concepts of Real-Gas Mixtures, Gas Ideal-Solutions, and Perfect-Gas Mixtures

    ERIC Educational Resources Information Center

    Privat, Romain; Jaubert, Jean-Noël; Moine, Edouard

    2016-01-01

    In many textbooks of chemical-engineering thermodynamics, a gas mixture obeying the fundamental law pV[subscript m] = RT is most often called ideal-gas mixture (in some rare cases, the term perfect-gas mixture can be found). These textbooks also define the fundamental concept of ideal solution which in theory, can be applied indifferently to…

  3. Unidirectional perfect absorber

    NASA Astrophysics Data System (ADS)

    Jin, L.; Wang, P.; Song, Z.

    2016-09-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices.

  4. Unidirectional perfect absorber

    PubMed Central

    Jin, L.; Wang, P.; Song, Z.

    2016-01-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices. PMID:27615125

  5. Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter

    NASA Astrophysics Data System (ADS)

    Ruffio, Jean-Baptiste; Macintosh, Bruce; Wang, Jason J.; Pueyo, Laurent; Nielsen, Eric L.; De Rosa, Robert J.; Czekala, Ian; Marley, Mark S.; Arriaga, Pauline; Bailey, Vanessa P.; Barman, Travis; Bulger, Joanna; Chilcote, Jeffrey; Cotten, Tara; Doyon, Rene; Duchêne, Gaspard; Fitzgerald, Michael P.; Follette, Katherine B.; Gerard, Benjamin L.; Goodsell, Stephen J.; Graham, James R.; Greenbaum, Alexandra Z.; Hibon, Pascale; Hung, Li-Wei; Ingraham, Patrick; Kalas, Paul; Konopacky, Quinn; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Marois, Christian; Metchev, Stanimir; Millar-Blanchaer, Maxwell A.; Morzinski, Katie M.; Oppenheimer, Rebecca; Palmer, David; Patience, Jennifer; Perrin, Marshall; Poyneer, Lisa; Rajan, Abhijith; Rameau, Julien; Rantakyrö, Fredrik T.; Savransky, Dmitry; Schneider, Adam C.; Sivaramakrishnan, Anand; Song, Inseok; Soummer, Remi; Thomas, Sandrine; Wallace, J. Kent; Ward-Duong, Kimberly; Wiktorowicz, Sloane; Wolff, Schuyler

    2017-06-01

    We present a new matched-filter algorithm for direct detection of point sources in the immediate vicinity of bright stars. The stellar point-spread function (PSF) is first subtracted using a Karhunen-Loéve image processing (KLIP) algorithm with angular and spectral differential imaging (ADI and SDI). The KLIP-induced distortion of the astrophysical signal is included in the matched-filter template by computing a forward model of the PSF at every position in the image. To optimize the performance of the algorithm, we conduct extensive planet injection and recovery tests and tune the exoplanet spectra template and KLIP reduction aggressiveness to maximize the signal-to-noise ratio (S/N) of the recovered planets. We show that only two spectral templates are necessary to recover any young Jovian exoplanets with minimal S/N loss. We also developed a complete pipeline for the automated detection of point-source candidates, the calculation of receiver operating characteristics (ROC), contrast curves based on false positives, and completeness contours. We process in a uniform manner more than 330 data sets from the Gemini Planet Imager Exoplanet Survey and assess GPI typical sensitivity as a function of the star and the hypothetical companion spectral type. This work allows for the first time a comparison of different detection algorithms at a survey scale accounting for both planet completeness and false-positive rate. We show that the new forward model matched filter allows the detection of 50% fainter objects than a conventional cross-correlation technique with a Gaussian PSF template for the same false-positive rate.

  6. Electrodynamics of Perfect Conductors

    NASA Astrophysics Data System (ADS)

    Fiolhais, Miguel C. N.; Essén, Hanno

    2013-05-01

    The most general electrodynamic equations of a perfect conducting state are obtained using a variational principle in a classical framework, following an approach by Pierre-Gilles de Gennes. London equations are derived as the time-independent case of these equations, corresponding to the magnetostatic minimal energy state of the perfect conducting system. For further confirmation, the same equations are also derived in the classical limit of the Coleman-Weinberg model, the most successful quantum macroscopic theory of superconductivity. The magnetic field expulsion is, therefore, a direct consequence of zero resistivity and not an exclusive property of superconductors.

  7. Application of Template Matching for Improving Classification of Urban Railroad Point Clouds

    PubMed Central

    Arastounia, Mostafa; Oude Elberink, Sander

    2016-01-01

    This study develops an integrated data-driven and model-driven approach (template matching) that clusters the urban railroad point clouds into three classes of rail track, contact cable, and catenary cable. The employed dataset covers 630 m of the Dutch urban railroad corridors in which there are four rail tracks, two contact cables, and two catenary cables. The dataset includes only geometrical information (three dimensional (3D) coordinates of the points) with no intensity data and no RGB data. The obtained results indicate that all objects of interest are successfully classified at the object level with no false positives and no false negatives. The results also show that an average 97.3% precision and an average 97.7% accuracy at the point cloud level are achieved. The high precision and high accuracy of the rail track classification (both greater than 96%) at the point cloud level stems from the great impact of the employed template matching method on excluding the false positives. The cables also achieve quite high average precision (96.8%) and accuracy (98.4%) due to their high sampling and isolated position in the railroad corridor. PMID:27973452

  8. Application of Template Matching for Improving Classification of Urban Railroad Point Clouds.

    PubMed

    Arastounia, Mostafa; Oude Elberink, Sander

    2016-12-12

    This study develops an integrated data-driven and model-driven approach (template matching) that clusters the urban railroad point clouds into three classes of rail track, contact cable, and catenary cable. The employed dataset covers 630 m of the Dutch urban railroad corridors in which there are four rail tracks, two contact cables, and two catenary cables. The dataset includes only geometrical information (three dimensional (3D) coordinates of the points) with no intensity data and no RGB data. The obtained results indicate that all objects of interest are successfully classified at the object level with no false positives and no false negatives. The results also show that an average 97.3% precision and an average 97.7% accuracy at the point cloud level are achieved. The high precision and high accuracy of the rail track classification (both greater than 96%) at the point cloud level stems from the great impact of the employed template matching method on excluding the false positives. The cables also achieve quite high average precision (96.8%) and accuracy (98.4%) due to their high sampling and isolated position in the railroad corridor.

  9. The Perfect Text.

    ERIC Educational Resources Information Center

    Russo, Ruth

    1998-01-01

    A chemistry teacher describes the elements of the ideal chemistry textbook. The perfect text is focused and helps students draw a coherent whole out of the myriad fragments of information and interpretation. The text would show chemistry as the central science necessary for understanding other sciences and would also root chemistry firmly in the…

  10. California's Perfect Storm

    ERIC Educational Resources Information Center

    Bacon, David

    2010-01-01

    The United States today faces an economic crisis worse than any since the Great Depression of the 1930s. Nowhere is it sharper than in the nation's schools. Last year, California saw a perfect storm of protest in virtually every part of its education system. K-12 teachers built coalitions with parents and students to fight for their jobs and their…

  11. California's Perfect Storm

    ERIC Educational Resources Information Center

    Bacon, David

    2010-01-01

    The United States today faces an economic crisis worse than any since the Great Depression of the 1930s. Nowhere is it sharper than in the nation's schools. Last year, California saw a perfect storm of protest in virtually every part of its education system. K-12 teachers built coalitions with parents and students to fight for their jobs and their…

  12. The Three Perfections

    ERIC Educational Resources Information Center

    Hinshaw, Craig

    2005-01-01

    For thousands of years, the three perfections--painting, poetry, and calligraphy--have been considered the mark of an enlightened person throughout Asian cultures. Fifth-grade students learned about these three hallmarks by studying three works from the Detroit Institute of Art's Asian collection: a nineteenth-century Japanese hand scroll, a…

  13. PERFECTIVE PARTICIPIALS IN HINDI.

    ERIC Educational Resources Information Center

    THIS PAPER DISCUSSES THE HINDI LANGUAGE SYNTAX OF PERFECTIVE PARTICIPIAL FORMS AS ADJECTIVES AND AS PARTICIPLES OF SEVERAL VARIETIES. THE FIRST PART OF THE REPORT DISTINGUISHES AND DESCRIBES EIGHT KINDS OF PARTICIPIAL USAGE AND SUGGESTS MORE GENERAL RULES FOR ANALYZING THESE USES. THE SECOND PART OFFERS A GENERATIVE DESCRIPTION OF THE SAME DATA.…

  14. The Perfect Politician

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    The perfect politician, the ideal political ally to a library, is often but not always an elected official. He or she is always an effective champion of "reasonable financial support," i.e., "the amount...which a thoroughly competent librarian can spend wisely." That is what J.T. Wyer, director of the New York State Library, said in his "What the…

  15. In a Perfect World

    ERIC Educational Resources Information Center

    Murray, Jeannette

    2010-01-01

    In a perfect world, all children should live at home with their family, play with the kids in their neighborhood, walk or ride the school bus to a community-based school--after affectionately kissing or hugging their parents goodbye. They should receive adequate classroom services and return home at 3 p.m. or thereabouts. They may even…

  16. The Three Perfections

    ERIC Educational Resources Information Center

    Hinshaw, Craig

    2005-01-01

    For thousands of years, the three perfections--painting, poetry, and calligraphy--have been considered the mark of an enlightened person throughout Asian cultures. Fifth-grade students learned about these three hallmarks by studying three works from the Detroit Institute of Art's Asian collection: a nineteenth-century Japanese hand scroll, a…

  17. In a Perfect World

    ERIC Educational Resources Information Center

    Murray, Jeannette

    2010-01-01

    In a perfect world, all children should live at home with their family, play with the kids in their neighborhood, walk or ride the school bus to a community-based school--after affectionately kissing or hugging their parents goodbye. They should receive adequate classroom services and return home at 3 p.m. or thereabouts. They may even…

  18. The Perfect Politician

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    The perfect politician, the ideal political ally to a library, is often but not always an elected official. He or she is always an effective champion of "reasonable financial support," i.e., "the amount...which a thoroughly competent librarian can spend wisely." That is what J.T. Wyer, director of the New York State Library, said in his "What the…

  19. Assessment and improvement of mapping algorithms for non-matching meshes and geometries in computational FSI

    NASA Astrophysics Data System (ADS)

    Wang, Tianyang; Wüchner, Roland; Sicklinger, Stefan; Bletzinger, Kai-Uwe

    2016-05-01

    This paper investigates data mapping between non-matching meshes and geometries in fluid-structure interaction. Mapping algorithms for surface meshes including nearest element interpolation, the standard mortar method and the dual mortar method are studied and comparatively assessed. The inconsistency problem of mortar methods at curved edges of fluid-structure-interfaces is solved by a newly developed enforcing consistency approach, which is robust enough to handle even the case that fluid boundary facets are totally not in contact with structure boundary elements due to high fluid refinement. Besides, tests with representative geometries show that the mortar methods are suitable for conservative mapping but it is better to use the nearest element interpolation in a direct way, and moreover, the dual mortar method can give slight oscillations. This work also develops a co-rotating mapping algorithm for 1D beam elements. Its novelty lies in the ability of handling large displacements and rotations.

  20. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    NASA Astrophysics Data System (ADS)

    Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.

    2014-12-01

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT

  1. A dynamic system matching technique for improving the accuracy of MEMS gyroscopes

    SciTech Connect

    Stubberud, Peter A.; Stubberud, Stephen C.; Stubberud, Allen R.

    2014-12-10

    A classical MEMS gyro transforms angular rates into electrical values through Euler's equations of angular rotation. Production models of a MEMS gyroscope will have manufacturing errors in the coefficients of the differential equations. The output signal of a production gyroscope will be corrupted by noise, with a major component of the noise due to the manufacturing errors. As is the case of the components in an analog electronic circuit, one way of controlling the variability of a subsystem is to impose extremely tight control on the manufacturing process so that the coefficient values are within some specified bounds. This can be expensive and may even be impossible as is the case in certain applications of micro-electromechanical (MEMS) sensors. In a recent paper [2], the authors introduced a method for combining the measurements from several nominally equal MEMS gyroscopes using a technique based on a concept from electronic circuit design called dynamic element matching [1]. Because the method in this paper deals with systems rather than elements, it is called a dynamic system matching technique (DSMT). The DSMT generates a single output by randomly switching the outputs of several, nominally identical, MEMS gyros in and out of the switch output. This has the effect of 'spreading the spectrum' of the noise caused by the coefficient errors generated in the manufacture of the individual gyros. A filter can then be used to eliminate that part of the spread spectrum that is outside the pass band of the gyro. A heuristic analysis in that paper argues that the DSMT can be used to control the effects of the random coefficient variations. In a follow-on paper [4], a simulation of a DSMT indicated that the heuristics were consistent. In this paper, analytic expressions of the DSMT noise are developed which confirm that the earlier conclusions are valid. These expressions include the various DSMT design parameters and, therefore, can be used as design tools for DSMT

  2. Use of an Improved Matching Algorithm to Select Scaffolds for Enzyme Design Based on a Complex Active Site Model

    PubMed Central

    Huang, Xiaoqiang; Xue, Jing; Lin, Min; Zhu, Yushan

    2016-01-01

    Active site preorganization helps native enzymes electrostatically stabilize the transition state better than the ground state for their primary substrates and achieve significant rate enhancement. In this report, we hypothesize that a complex active site model for active site preorganization modeling should help to create preorganized active site design and afford higher starting activities towards target reactions. Our matching algorithm ProdaMatch was improved by invoking effective pruning strategies and the native active sites for ten scaffolds in a benchmark test set were reproduced. The root-mean squared deviations between the matched transition states and those in the crystal structures were < 1.0 Å for the ten scaffolds, and the repacking calculation results showed that 91% of the hydrogen bonds within the active sites are recovered, indicating that the active sites can be preorganized based on the predicted positions of transition states. The application of the complex active site model for de novo enzyme design was evaluated by scaffold selection using a classic catalytic triad motif for the hydrolysis of p-nitrophenyl acetate. Eighty scaffolds were identified from a scaffold library with 1,491 proteins and four scaffolds were native esterase. Furthermore, enzyme design for complicated substrates was investigated for the hydrolysis of cephalexin using scaffold selection based on two different catalytic motifs. Only three scaffolds were identified from the scaffold library by virtue of the classic catalytic triad-based motif. In contrast, 40 scaffolds were identified using a more flexible, but still preorganized catalytic motif, where one scaffold corresponded to the α-amino acid ester hydrolase that catalyzes the hydrolysis and synthesis of cephalexin. Thus, the complex active site modeling approach for de novo enzyme design with the aid of the improved ProdaMatch program is a promising approach for the creation of active sites with high catalytic

  3. Use of an Improved Matching Algorithm to Select Scaffolds for Enzyme Design Based on a Complex Active Site Model.

    PubMed

    Huang, Xiaoqiang; Xue, Jing; Lin, Min; Zhu, Yushan

    2016-01-01

    Active site preorganization helps native enzymes electrostatically stabilize the transition state better than the ground state for their primary substrates and achieve significant rate enhancement. In this report, we hypothesize that a complex active site model for active site preorganization modeling should help to create preorganized active site design and afford higher starting activities towards target reactions. Our matching algorithm ProdaMatch was improved by invoking effective pruning strategies and the native active sites for ten scaffolds in a benchmark test set were reproduced. The root-mean squared deviations between the matched transition states and those in the crystal structures were < 1.0 Å for the ten scaffolds, and the repacking calculation results showed that 91% of the hydrogen bonds within the active sites are recovered, indicating that the active sites can be preorganized based on the predicted positions of transition states. The application of the complex active site model for de novo enzyme design was evaluated by scaffold selection using a classic catalytic triad motif for the hydrolysis of p-nitrophenyl acetate. Eighty scaffolds were identified from a scaffold library with 1,491 proteins and four scaffolds were native esterase. Furthermore, enzyme design for complicated substrates was investigated for the hydrolysis of cephalexin using scaffold selection based on two different catalytic motifs. Only three scaffolds were identified from the scaffold library by virtue of the classic catalytic triad-based motif. In contrast, 40 scaffolds were identified using a more flexible, but still preorganized catalytic motif, where one scaffold corresponded to the α-amino acid ester hydrolase that catalyzes the hydrolysis and synthesis of cephalexin. Thus, the complex active site modeling approach for de novo enzyme design with the aid of the improved ProdaMatch program is a promising approach for the creation of active sites with high catalytic

  4. Symmetry matched auditory cues improve gait steadiness in most people with Parkinson's disease but not in healthy older people.

    PubMed

    Brodie, Matthew A D; Dean, Roger T; Beijer, Tim R; Canning, Colleen G; Smith, Stuart T; Menant, Jasmine C; Lord, Stephen R

    2015-01-01

    Unsteady gait and falls are major problems for people with Parkinson's disease (PD). Symmetric auditory cues at altered cadences have been used to improve walking speed or step length. However, few people are exactly symmetric in terms of morphology or movement patterns and effects of symmetric cueing on gait steadiness are inconclusive. To investigate if matching auditory cue a/symmetry to an individual's intrinsic symmetry or asymmetry affects gait steadiness, gait symmetry, and comfort to cues, in people with PD, healthy age-matched controls (HAM) and young. Thirty participants; 10 with PD, 11 HAM (66 years), and 9 young (30 years), completed five baseline walks (no cues) and twenty-five cued walks at habitual cadence but different a/symmetries. Outcomes included; gait steadiness (step time variability and smoothness by harmonic ratios), walking speed, symmetry, comfort, and cue lag times. Without cues, PD participants had slower and less steady gait than HAM or young. Gait symmetry was distinct from gait steadiness, and unaffected by cue symmetry or a diagnosis of PD, but associated with aging. All participants maintained preferred gait symmetry and lag times independent of cue symmetry. When cues were matched to the individual's habitual gait symmetry and cadence: Gait steadiness improved in the PD group, but deteriorated in the HAM controls, and was unchanged in the young. Gait outcomes worsened for the two PD participants who reported discomfort to cued walking and had high New Freezing of Gait scores. It cannot be assumed all individuals benefit equally from auditory cues. Symmetry matched auditory cues compensated for unsteady gait in most people with PD, but interfered with gait steadiness in older people without basal ganglia deficits.

  5. Improved ventilation-perfusion matching with increasing abdominal pressure during CO(2) -pneumoperitoneum in pigs.

    PubMed

    Strang, C M; Freden, F; Maripuu, E; Ebmeyer, U; Hachenberg, T; Hedenstierna, Göran

    2011-08-01

    CO(2) -pneumoperitoneum (PP) is performed at varying abdominal pressures. We studied in an animal preparation the effect of increasing abdominal pressures on gas exchange during PP. Eighteen anaesthetized pigs were studied. Three abdominal pressures (8, 12 and 16 mmHg) were randomly selected in each animal. In six pigs, single-photon emission computed tomography (SPECT) was used for the analysis of V/Q distributions; in another six pigs, multiple inert gas elimination technique (MIGET) was used for assessing V/Q matching. In further six pigs, computed tomography (CT) was performed for the analysis of regional aeration. MIGET, CT and central haemodynamics and pulmonary gas exchange were recorded during anaesthesia and after 60 min on each of the three abdominal pressures. SPECT was performed three times, corresponding to each PP level. Atelectasis, as assessed by CT, increased during PP and in proportion to abdominal pressure [from 9 ± 2% (mean ± standard deviation) at 8 mmHg to 15 ± 2% at 16 mmHg, P<0.05]. SPECT during increasing abdominal CO(2) pressures showed a shift of blood flow towards better ventilated areas. V/Q analysis by MIGET showed no change in shunt during 8 mmHg PP (9 ± 1.9% compared with baseline 9 ± 1.2%) but a decrease during 12 mmHg PP (7 ± 0.9%, P<0.05) and 16 mmHg PP (5 ± 1%, P<0.01). PaO(2) increased from 39 ± 10 to 52 ± 9 kPa (baseline to 16 mmHg PP, P<0.01). Arterial carbon dioxide (PCO(2) ) increased during PP and increased further with increasing abdominal pressures. With increasing abdominal pressure during PP perfusion was redistributed more than ventilation away from dorsal, collapsed lung regions. This resulted in a better V/Q match. A possible mechanism is enhanced hypoxic pulmonary vasoconstriction mediated by increasing PCO(2) . © 2011 The Authors. Acta Anaesthesiologica Scandinavica © 2011 The Acta Anaesthesiologica Scandinavica Foundation.

  6. GlideScope Use improves intubation success rates: an observational study using propensity score matching.

    PubMed

    Ibinson, James W; Ezaru, Catalin S; Cormican, Daniel S; Mangione, Michael P

    2014-01-01

    Rigid video laryngoscopes are popular alternatives to direct laryngoscopy for intubation, but further large scale prospective studies comparing these devices to direct laryngoscopy in routine anesthesiology practice are needed. We hypothesized that the first pass success rate with one particular video laryngoscope, the GlideScope, would be higher than the success rate with direct laryngoscopy. 3831 total intubation attempts were tracked in an observational study comparing first-pass success rate using a Macintosh or Miller-style laryngoscope with the GlideScope. Propensity scoring was then used to select 626 subjects matched between the two groups based on their morphologic traits. Comparing the GlideScope and direct laryngoscopy groups suggested that intubation would be more difficult in the GlideScope group based on the Mallampati class, cervical range of motion, mouth opening, dentition, weight, and past intubation history. Thus, a propensity score based on these factors was used to balance the groups into two 313 patient cohorts. Direct laryngoscopy was successful in 80.8% on the first-pass intubation attempt, while the GlideScope was successful in 93.6% (p <0.001; risk difference of 0.128 with a 95% CI of 0.0771 - 0.181). A greater first-attempt success rate was found when using the GlideScope versus direct laryngoscopy. In addition, the GlideScope was found to be 99% successful for intubation after initial failure of direct laryngoscopy, helping to reduce the incidence of failed intubation.

  7. On Improving Analytical Models of Cosmic Reionization for Matching Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Kaurov, Alexander A.

    2016-11-01

    The methods for studying the epoch of cosmic reionization vary from full radiative transfer simulations to purely analytical models. While numerical approaches are computationally expensive and are not suitable for generating many mock catalogs, analytical methods are based on assumptions and approximations. We explore the interconnection between both methods. First, we ask how the analytical framework of excursion set formalism can be used for statistical analysis of numerical simulations and visual representation of the morphology of ionization fronts. Second, we explore the methods of training the analytical model on a given numerical simulation. We present a new code which emerged from this study. Its main application is to match the analytical model with a numerical simulation. Then, it allows one to generate mock reionization catalogs with volumes exceeding the original simulation quickly and computationally inexpensively, meanwhile reproducing large-scale statistical properties. These mock catalogs are particularly useful for cosmic microwave background polarization and 21 cm experiments, where large volumes are required to simulate the observed signal.

  8. On Improving Analytical Models of Cosmic Reionization for Matching Numerical Simulations

    SciTech Connect

    Kaurov, Alexander A.

    2016-01-01

    The methods for studying the epoch of cosmic reionization vary from full radiative transfer simulations to purely analytical models. While numerical approaches are computationally expensive and are not suitable for generating many mock catalogs, analytical methods are based on assumptions and approximations. We explore the interconnection between both methods. First, we ask how the analytical framework of excursion set formalism can be used for statistical analysis of numerical simulations and visual representation of the morphology of ionization fronts. Second, we explore the methods of training the analytical model on a given numerical simulation. We present a new code which emerged from this study. Its main application is to match the analytical model with a numerical simulation. Then, it allows one to generate mock reionization catalogs with volumes exceeding the original simulation quickly and computationally inexpensively, meanwhile reproducing large scale statistical properties. These mock catalogs are particularly useful for CMB polarization and 21cm experiments, where large volumes are required to simulate the observed signal.

  9. RHIC The Perfect Liquid

    ScienceCinema

    BNL

    2016-07-12

    Evidence to date suggests that gold-gold collisions the Relativistic Heavy Ion Collider at Brookhaven are indeed creating a new state of hot, dense matter, but one quite different and even more remarkable than had been predicted. Instead of behaving like a gas of free quarks and gluons, as was expected, the matter created in RHIC's heavy ion collisions appears to be more like a "perfect" liquid.

  10. RHIC The Perfect Liquid

    SciTech Connect

    BNL

    2008-08-12

    Evidence to date suggests that gold-gold collisions the Relativistic Heavy Ion Collider at Brookhaven are indeed creating a new state of hot, dense matter, but one quite different and even more remarkable than had been predicted. Instead of behaving like a gas of free quarks and gluons, as was expected, the matter created in RHIC's heavy ion collisions appears to be more like a "perfect" liquid.

  11. Optical object detection in paper improved by refractive index matching and mechanical treatment

    NASA Astrophysics Data System (ADS)

    Saarela, J.; Heikkinen, S.; Fabritius, T.; Myllylä, R.

    2008-06-01

    Two different paper grades were tested with a clearing agent to measure how much mechanical smoothening can improve transparency inside paper. The paper grades were newsprint and supercalendered paper. The paper furnishes of both papers were alike, but the supercalendered paper was mechanically smoothened. Anise oil was used as the clearing agent, but similar measurements were also done with air and water. Black lines 8.5 μm to 281.1 μm wide were placed behind layers of cleared paper and transparency was measured with a microscope. When anise oil was the clearing agent, supercalendering improved transparent paper grammage from 139 g/m2 to 164 g/m2. With water the improvement was from 40 g/m2 to 51 g/m2. With air the improvement was not determinable. As a conclusion, it is recommended that paper is smoothened if it needs to be studied optically. Optical coherence tomography, for example, would benefit from this treatment.

  12. Ultra-Perfect Sorting Scenarios

    NASA Astrophysics Data System (ADS)

    Ouangraoua, Aïda; Bergeron, Anne; Swenson, Krister M.

    Perfection has been used as a criteria to select rearrangement scenarios since 2004. However, there is a fundamental bias towards extant species in the original definition: ancestral species are not bound to perfection. Here we develop a new theory of perfection that takes an egalitarian view of species, and apply it to the complex evolution of mammal chromosome X.

  13. Improved three-dimensional Fourier domain optical coherence tomography by index matching in alveolar structures

    NASA Astrophysics Data System (ADS)

    Meissner, Sven; Knels, Lilla; Koch, Edmund

    2009-11-01

    Three-dimensional Fourier domain optical coherence tomography (3-D FDOCT) is used to demonstrate that perfusion fixation with a mixture of glutaraldehyde and paraformaldehyde does not alter the geometry of subpleural lung parenchyma in isolated and perfused rabbit lungs. This is confirmed by simultaneous imaging of lung parenchyma with intravital microscopy. To eliminate the diffraction index interfaces between alveolar pockets and walls, we fill the fixed lungs with ethanol by perfusing with gradually increasing concentrations. This bottom-up filling process leaves no remaining air bubbles in the alveolar structures, thus drastically improving the resolution and penetration depth of 3-D FDOCT imaging. We observe an approximately 18% increase in alveolar area after ethanol filling, likely due in large part to elimination of the air/tissue interfaces. 3-D OCT datasets acquired from ethanol-filled lungs allow segmentation of the ethanol-filled structures, which were formerly air-filled, and 3-D reconstruction of larger areas of subpleural alveolar structures. Our innovative process of filling the lungs with ethanol postperfusion fixation thus enables more accurate quantification of alveolar geometries, a critical component of modeling lung function.

  14. Improving pediatric cardiac surgical care in developing countries: matching resources to needs.

    PubMed

    Dearani, Joseph A; Neirotti, Rodolfo; Kohnke, Emily J; Sinha, Kingshuk K; Cabalka, Allison K; Barnes, Roxann D; Jacobs, Jeffrey P; Stellin, Giovanni; Tchervenkov, Christo I; Cushing, John C

    2010-01-01

    This article reviews a systematic approach to the design and support of pediatric cardiac surgery programs in the developing world with the guidance and strategies of Children's HeartLink, an experienced non-government organization for more than 40 years. An algorithm with criteria for the selection of a partner site is outlined. A comprehensive education strategy from the physician to the allied health care provider is the mainstay for successful program development. In a partner program, the road to successful advancement and change depends on many factors, such as government support, hospital administration support, medical staff leadership, and a committed and motivated faculty with requisite skills, incentives, and resources. In addition to these factors, it is essential that the development effort includes considerations of environment (eg, governmental support, regulatory environment, and social structure) and health system (elements related to affordability, access, and awareness of care) that impact success. Partner programs should be willing to initiate a clinical database with the intent to analyze and critique their results to optimize quality assurance and improve outcomes. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  15. Universal evolution of perfect lenses.

    PubMed

    Wee, W H; Pendry, J B

    2011-04-22

    This Letter is a theoretical attempt to answer two questions. First how long does it takes for perfect lensing to be observed, and second how does loss diminish the performance of a general perfect lens. The method described in this Letter is universal, in the sense that it can be applied to perfect lenses of any arbitrary geometry. We shall show that the dynamics of perfect lensing is equivalent to the dynamics of 2 coupled simple harmonic oscillators. Moreover we shall derive quantitatively, the effects of losses on a compact perfect lens.

  16. Improved peptide mass fingerprinting matches via optimized sample preparation in MALDI mass spectrometry.

    PubMed

    Padliya, Neerav D; Wood, Troy D

    2008-10-03

    Peptide mass fingerprinting (PMF) is a powerful technique in which experimentally measured m/z values of peptides resulting from a protein digest form the basis for a characteristic fingerprint of the intact protein. Due to its propensity to generate singly charged ions, along with its relative insensitivity to salts and buffers, matrix-assisted laser desorption and ionization (MALDI)-time-of-flight mass spectrometry (TOFMS) is the MS method of choice for PMF. The qualitative features of the mass spectrum can be selectively tuned by employing different methods to prepare the protein digest and matrix for MALDI-TOFMS. The selective tuning of MALDI mass spectra in order to optimize PMF is addressed here. Bovine serum albumin, carbonic anhydrase, cytochrome c, hemoglobin alpha- and beta-chain, and myoglobin were digested with trypsin and then analyzed by MALDI-TOFMS. 2,5-dihydroxybenzoic acid (DHB) and alpha-cyano-4-hydroxycinnamic acid (CHCA) were prepared using six different sample preparation methods: dried droplet, application of protein digest on MALDI plate followed by addition of matrix, dried droplet with vacuum drying, overlayer, sandwich, and dried droplet with heating. Improved results were obtained for the matrix alpha-cyano-4-hydroxycinnamic acid using a modification of the died droplet method in which the MALDI plate was heated to 80 degrees C prior to matrix application, which is supported by observations from scanning electron microscopy. Although each protein was found to have a different optimum sample preparation method for PMF, in general higher sequence coverage for PMF was obtained using DHB. The best PMF results were obtained when all of the mass spectral data for a particular protein digest was convolved together.

  17. Lattice-Matched InGaAs–InAlAs Core–Shell Nanowires with Improved Luminescence and Photoresponse Properties

    PubMed Central

    2015-01-01

    Core–shell nanowires (NW) have become very prominent systems for band engineered NW heterostructures that effectively suppress detrimental surface states and improve performance of related devices. This concept is particularly attractive for material systems with high intrinsic surface state densities, such as the low-bandgap In-containing group-III arsenides, however selection of inappropriate, lattice-mismatched shell materials have frequently caused undesired strain accumulation, defect formation, and modifications of the electronic band structure. Here, we demonstrate the realization of closely lattice-matched radial InGaAs–InAlAs core–shell NWs tunable over large compositional ranges [x(Ga)∼y(Al) = 0.2–0.65] via completely catalyst-free selective-area molecular beam epitaxy. On the basis of high-resolution X-ray reciprocal space maps the strain in the NW core is found to be insignificant (ε < 0.1%), which is further reflected by the absence of strain-induced spectral shifts in luminescence spectra and nearly unmodified band structure. Remarkably, the lattice-matched InAlAs shell strongly enhances the optical efficiency by up to 2 orders of magnitude, where the efficiency enhancement scales directly with increasing band offset as both Ga- and Al-contents increase. Ultimately, we fabricated vertical InGaAs−InAlAs NW/Si photovoltaic cells and show that the enhanced internal quantum efficiency is directly translated to an energy conversion efficiency that is ∼3–4 times larger as compared to an unpassivated cell. These results highlight the promising performance of lattice-matched III–V core–shell NW heterostructures with significant impact on future development of related nanophotonic and electronic devices. PMID:25922974

  18. Lattice-Matched InGaAs-InAlAs Core-Shell Nanowires with Improved Luminescence and Photoresponse Properties.

    PubMed

    Treu, Julian; Stettner, Thomas; Watzinger, Marc; Morkötter, Stefanie; Döblinger, Markus; Matich, Sonja; Saller, Kai; Bichler, Max; Abstreiter, Gerhard; Finley, Jonathan J; Stangl, Julian; Koblmüller, Gregor

    2015-05-13

    Core-shell nanowires (NW) have become very prominent systems for band engineered NW heterostructures that effectively suppress detrimental surface states and improve performance of related devices. This concept is particularly attractive for material systems with high intrinsic surface state densities, such as the low-bandgap In-containing group-III arsenides, however selection of inappropriate, lattice-mismatched shell materials have frequently caused undesired strain accumulation, defect formation, and modifications of the electronic band structure. Here, we demonstrate the realization of closely lattice-matched radial InGaAs-InAlAs core-shell NWs tunable over large compositional ranges [x(Ga)∼y(Al) = 0.2-0.65] via completely catalyst-free selective-area molecular beam epitaxy. On the basis of high-resolution X-ray reciprocal space maps the strain in the NW core is found to be insignificant (ε < 0.1%), which is further reflected by the absence of strain-induced spectral shifts in luminescence spectra and nearly unmodified band structure. Remarkably, the lattice-matched InAlAs shell strongly enhances the optical efficiency by up to 2 orders of magnitude, where the efficiency enhancement scales directly with increasing band offset as both Ga- and Al-contents increase. Ultimately, we fabricated vertical InGaAs-InAlAs NW/Si photovoltaic cells and show that the enhanced internal quantum efficiency is directly translated to an energy conversion efficiency that is ∼3-4 times larger as compared to an unpassivated cell. These results highlight the promising performance of lattice-matched III-V core-shell NW heterostructures with significant impact on future development of related nanophotonic and electronic devices.

  19. High Resolution Direction of Arrival (DOA) Estimation Based on Improved Orthogonal Matching Pursuit (OMP) Algorithm by Iterative Local Searching

    PubMed Central

    Wang, Wenyi; Wu, Renbiao

    2013-01-01

    DOA (Direction of Arrival) estimation is a major problem in array signal processing applications. Recently, compressive sensing algorithms, including convex relaxation algorithms and greedy algorithms, have been recognized as a kind of novel DOA estimation algorithm. However, the success of these algorithms is limited by the RIP (Restricted Isometry Property) condition or the mutual coherence of measurement matrix. In the DOA estimation problem, the columns of measurement matrix are steering vectors corresponding to different DOAs. Thus, it violates the mutual coherence condition. The situation gets worse when there are two sources from two adjacent DOAs. In this paper, an algorithm based on OMP (Orthogonal Matching Pursuit), called ILS-OMP (Iterative Local Searching-Orthogonal Matching Pursuit), is proposed to improve DOA resolution by Iterative Local Searching. Firstly, the conventional OMP algorithm is used to obtain initial estimated DOAs. Then, in each iteration, a local searching process for every estimated DOA is utilized to find a new DOA in a given DOA set to further decrease the residual. Additionally, the estimated DOAs are updated by substituting the initial DOA with the new one. The simulation results demonstrate the advantages of the proposed algorithm. PMID:23974150

  20. In search of perfect reads.

    PubMed

    Pal, Soumitra; Aluru, Srinivas

    2015-01-01

    Continued advances in next generation short-read sequencing technologies are increasing throughput and read lengths, while driving down error rates. Taking advantage of the high coverage sampling used in many applications, several error correction algorithms have been developed to improve data quality further. However, correcting errors in high coverage sequence data requires significant computing resources. We propose a different approach to handle erroneous sequence data. Presently, error rates of high-throughput platforms such as the Illumina HiSeq are within 1%. Moreover, the errors are not uniformly distributed in all reads, and a large percentage of reads are indeed error-free. Ability to predict such perfect reads can significantly impact the run-time complexity of applications. We present a simple and fast k-spectrum analysis based method to identify error-free reads. The filtration process to identify and weed out erroneous reads can be customized at several levels of stringency depending upon the downstream application need. Our experiments show that if around 80% of the reads in a dataset are perfect, then our method retains almost 99.9% of them with more than 90% precision rate. Though filtering out reads identified as erroneous by our method reduces the average coverage by about 7%, we found the remaining reads provide as uniform a coverage as the original dataset. We demonstrate the effectiveness of our approach on an example downstream application: we show that an error correction algorithm, Reptile, which rely on collectively analyzing the reads in a dataset to identify and correct erroneous bases, instead use reads predicted to be perfect by our method to correct the other reads, the overall accuracy improves further by up to 10%. Thanks to the continuous technological improvements, the coverage and accuracy of reads from dominant sequencing platforms have now reached an extent where we can envision just filtering out reads with errors, thus making

  1. Constrained matched filtering for extended dynamic range and improved noise rejection for Shack-Hartmann wavefront sensing.

    PubMed

    Gilles, L; Ellerbroek, B L

    2008-05-15

    We recently introduced matched filtering in the context of astronomical Shack-Hartmann wavefront sensing with elongated sodium laser beacons [Appl. Opt. 45, 6568 (2006)]. Detailed wave optics Monte Carlo simulations implementing this technique for the Thirty Meter Telescope dual conjugate adaptive optics system have, however, revealed frequent bursts of degraded closed loop residual wavefront error [Proc. SPIE 6272, 627236 (2006)]. The origin of this problem is shown to be related to laser guide star jitter on the sky that kicks the filter out of its linear dynamic range, which leads to bursts of nonlinearities that are reconstructed into higher-order wavefront aberrations, particularly coma and trifoil for radially elongated subaperture spots. An elegant reformulation of the algorithm is proposed to extend its dynamic range using a set of linear constraints while preserving its improved noise rejection and Monte Carlo performance results are reported that confirm the benefits of the method.

  2. Evaluation of a Novel Computer Color Matching System Based on the Improved Back-Propagation Neural Network Model.

    PubMed

    Wei, Jiaqiang; Peng, Mengdong; Li, Qing; Wang, Yining

    2016-11-09

    To explore the feasibility of a novel computer color-matching (CCM) system based on the improved back-propagation neural network (BPNN) model by comparing it with the traditional visual method. Forty-three metal-ceramic specimens were fabricated by proportionally mixing porcelain powders. Thirty-nine specimens were randomly selected to train the BPNN model, while the remaining four specimens were used to test and calibrate the model. A CCM system based on the improved BPNN model was constructed using MATLAB software. A comparison of the novel CCM system and the traditional visual method was conducted by evaluating the color reproduction results of 10 maxillary central incisors. Metal-ceramic specimens were fabricated using two color reproduction approaches. Color distributions (L*, a*, and b*) of the target teeth and of the corresponding metal-ceramic specimens were measured using a spectroradiometer. Color differences (ΔE) and color distributions (ΔL*, Δa*, and Δb*) between the teeth and their corresponding specimens were calculated. The average ΔE value of the CCM system was 1.89 ± 0.75, which was lower than that of the visual approach (3.54 ± 1.11, p < 0.01). With respect to color distributions, substantial differences were found between the two color-matching systems, except for ΔL* (p > 0.05). The novel CCM system produced greater accuracy in color reproduction within the given color space than the traditional visual approach. © 2016 by the American College of Prosthodontists.

  3. Does smoking cessation result in improved mental health? A comparison of regression modelling and propensity score matching

    PubMed Central

    Taylor, Gemma; Girling, Alan; McNeill, Ann; Aveyard, Paul

    2015-01-01

    Objectives Smokers report that smoking is therapeutic; a recent meta-analysis suggests the contrary. However, the association in that review may be explained by group-membership bias and confounding. Propensity score matching (PSM) aims to produce causal estimates from observational data. We examined the association between cessation and change in mental health before and after PSM. Design A secondary analysis of prospective data from 5 placebo-controlled randomised trials for smoking reduction. Participants All participants were adult smokers and had smoked for at least 3 years. Participants were excluded if they were pregnant, breast feeding, under psychiatric care, deemed to be unfit by a general practitioner or part of a cessation programme. In total, 937 participants provided smoking data at both 6-month and 12-month follow-ups. Of these, 68 were confirmed as abstinent at both 6 and 12 months and 589 as continuous smokers at both follow-ups. Primary outcome Change in mental health (36-item Short Form Survey (SF-36), scored 0–100) from baseline (while all participants were smokers) to 12-month follow-up (after cessation) was compared between quitters and continuing smokers with and without adjustment, and after PSM. Results Before matching, quitters’ mental health scores improved compared with continuing smokers’, the mean difference and 95% CI was 5.5 (1.6 to 9.4). After adjustment, the difference was 4.5 (0.6 to 8.5), and after PSM, the difference was 3.4 (−2.2 to 8.9). Conclusions Improvements in mental health after smoking cessation may be partly but not completely explained by group membership bias and confounding. PMID:26490099

  4. Making clinical trials more relevant: improving and validating the PRECIS tool for matching trial design decisions to trial purpose.

    PubMed

    Loudon, Kirsty; Zwarenstein, Merrick; Sullivan, Frank; Donnan, Peter; Treweek, Shaun

    2013-04-27

    If you want to know which of two or more healthcare interventions is most effective, the randomised controlled trial is the design of choice. Randomisation, however, does not itself promote the applicability of the results to situations other than the one in which the trial was done. A tool published in 2009, PRECIS (PRagmatic Explanatory Continuum Indicator Summaries) aimed to help trialists design trials that produced results matched to the aim of the trial, be that supporting clinical decision-making, or increasing knowledge of how an intervention works. Though generally positive, groups evaluating the tool have also found weaknesses, mainly that its inter-rater reliability is not clear, that it needs a scoring system and that some new domains might be needed. The aim of the study is to: Produce an improved and validated version of the PRECIS tool. Use this tool to compare the internal validity of, and effect estimates from, a set of explanatory and pragmatic trials matched by intervention. The study has four phases. Phase 1 involves brainstorming and a two-round Delphi survey of authors who cited PRECIS. In Phase 2, the Delphi results will then be discussed and alternative versions of PRECIS-2 developed and user-tested by experienced trialists. Phase 3 will evaluate the validity and reliability of the most promising PRECIS-2 candidate using a sample of 15 to 20 trials rated by 15 international trialists. We will assess inter-rater reliability, and raters' subjective global ratings of pragmatism compared to PRECIS-2 to assess convergent and face validity. Phase 4, to determine if pragmatic trials sacrifice internal validity in order to achieve applicability, will compare the internal validity and effect estimates of matched explanatory and pragmatic trials of the same intervention, condition and participants. Effect sizes for the trials will then be compared in a meta-regression. The Cochrane Risk of Bias scores will be compared with the PRECIS-2 scores of

  5. A perfect launch

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Billows of smoke and steam spread across Launch Pad 39A as Space Shuttle Discovery lifts off on mission STS-92 to the International Space Station. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.

  6. Perfect and Near-Perfect Adaptation in Cell Signaling.

    PubMed

    Ferrell, James E

    2016-02-24

    Adaptation is an important basic feature of cellular regulation. Previous theoretical work has identified three types of circuits-negative feedback loops, incoherent feedforward systems, and state-dependent inactivation systems-that can achieve perfect or near-perfect adaptation. Recent work has added another strategy, termed antithetic integral feedback, to the list of motifs capable of robust perfect adaptation. Here, we discuss the properties, limitations, and biological relevance of each of these circuits.

  7. Improving food composition data quality: Three new FAO/INFOODS guidelines on conversions, data evaluation and food matching.

    PubMed

    Charrondiere, U Ruth; Rittenschober, Doris; Nowak, Verena; Stadlmayr, Barbara; Wijesinha-Bettoni, Ramani; Haytowitz, David

    2016-02-15

    Food composition data play a key role in many sectors and the availability of quality data is critically important. Since 1984, the International Network of Food Data Systems (INFOODS) has been working towards improving food composition data quality and availability, including the development and updating of standards, guidelines and tools for food composition. FAO/INFOODS has recently published three comprehensive guidelines to improve and harmonise the compilation of data: (1) Guidelines for Food Matching, (2) Guidelines for Checking Food Composition Data prior to Publication of a User Table/Database, and (3) Guidelines for Converting Units, Denominators and Expressions. This article describes their content and development processes. Their adoption, along with additional ones planned for the future by FAO/INFOODS, should further improve the quality of published food composition data, which in turn can lead to more accurate nutrient intake estimates and more precise food labels, as well as better-targeted programs and policies. Copyright © 2015 Food and Agriculture Organization of the United Nations (FAO). Published by Elsevier Ltd.. All rights reserved.

  8. Literacy Design Collaborative and Struggling Readers: A Perfect Match

    ERIC Educational Resources Information Center

    Southern Regional Education Board (SREB), 2014

    2014-01-01

    In Florida, middle grades students take the Florida Comprehensive Assessment Test 2.0 (FCAT 2.0) in reading and writing. In partnership with the Southern Regional Education Board (SREB), Avalon Middle School implemented the Literacy Design Collaborative (LDC) framework beginning in the 2012-2013 school year to develop literacy skills across…

  9. Soil Respiration and Student Inquiry: A Perfect Match

    ERIC Educational Resources Information Center

    Hoyt, Catherine Marie; Wallenstein, Matthew David

    2011-01-01

    This activity explores the cycling of carbon between the atmosphere (primarily as CO[subscript 2]) and biomass in plants, animals, and microscopic organisms. Students design soil respiration experiments using a protocol that resembles current practice in soil ecology. Three methods for measuring soil respiration are presented. Student-derived…

  10. Literacy Design Collaborative and Struggling Readers: A Perfect Match

    ERIC Educational Resources Information Center

    Southern Regional Education Board (SREB), 2014

    2014-01-01

    In Florida, middle grades students take the Florida Comprehensive Assessment Test 2.0 (FCAT 2.0) in reading and writing. In partnership with the Southern Regional Education Board (SREB), Avalon Middle School implemented the Literacy Design Collaborative (LDC) framework beginning in the 2012-2013 school year to develop literacy skills across…

  11. Literature Circles: A Perfect Match for Online Instruction

    ERIC Educational Resources Information Center

    Whittingham, Jeff

    2013-01-01

    This article describes the author's search for an appropriate and satisfying online teaching method. After experimenting with several methods (chat room, discussion board, student led discussion), the author reached back to his face-to-face classroom success with literature circles. This article reports the results of research conducted by the…

  12. Literature Circles: A Perfect Match for Online Instruction

    ERIC Educational Resources Information Center

    Whittingham, Jeff

    2013-01-01

    This article describes the author's search for an appropriate and satisfying online teaching method. After experimenting with several methods (chat room, discussion board, student led discussion), the author reached back to his face-to-face classroom success with literature circles. This article reports the results of research conducted by the…

  13. Solos and Adolescent Singers: Making the Perfect Match.

    ERIC Educational Resources Information Center

    Boardman, Susan; Alt, David

    1992-01-01

    Discusses the selection of material for vocal performances by high school students. Describes adolescent voices as young with little vocal technique and only partially developed or unused register. Includes considerations of breath management, tessitura, energy, subject matter, and language. Provides a list of songs meeting appropriate…

  14. Soil Respiration and Student Inquiry: A Perfect Match

    ERIC Educational Resources Information Center

    Hoyt, Catherine Marie; Wallenstein, Matthew David

    2011-01-01

    This activity explores the cycling of carbon between the atmosphere (primarily as CO[subscript 2]) and biomass in plants, animals, and microscopic organisms. Students design soil respiration experiments using a protocol that resembles current practice in soil ecology. Three methods for measuring soil respiration are presented. Student-derived…

  15. A Perfectly Matched Layer for Peridynamics in Two Dimensions

    DTIC Science & Technology

    2013-04-01

    family, Hx , a small, arbitrary value can be chosen as a cutoff for the kernel. Note that the cutoff has a large impact on the efficiency of the method...discretization, so it is better to use a smooth transition for φ. Here, we divide the PML region into two parts, one in which φ is a constant value , and...the other in which φ ramps up to that constant value following a Gaussian distribution. An example is shown in Figure 1, with the constant region set

  16. Nuclear Forces and High-Performance Computing: The Perfect Match

    SciTech Connect

    Luu, T; Walker-Loud, A

    2009-06-12

    High-performance computing is now enabling the calculation of certain nuclear interaction parameters directly from Quantum Chromodynamics, the quantum field theory that governs the behavior of quarks and gluons and is ultimately responsible for the nuclear strong force. We briefly describe the state of the field and describe how progress in this field will impact the greater nuclear physics community. We give estimates of computational requirements needed to obtain certain milestones and describe the scientific and computational challenges of this field.

  17. Improved efficiency of perovskite-silicon tandem solar cell near the matched optical absorption between the subcells

    NASA Astrophysics Data System (ADS)

    Iftiquar, S. M.; Jung, Junhee; Yi, Junsin

    2017-10-01

    Current matching in a tandem solar cell is significant, because in a mismatched device the lowest current generating subcell becomes the current limiting component, and overall device efficiency remains lower than that could be obtained in the current matched device. Recent reports on methyl ammonium lead iodide (MAPbI3) based thin film solar cell has drawn interest to a perovskite-silicon tandem solar cell. Therefore, we investigated such a tandem solar cell theoretically. We used a MAPbI3 based top and heterojunction with intrinsic thin layer silicon (HIT) bottom subcell. Optimization of the device structure was carried out by varying thickness of perovskite layer of top-cell from 50 to 1000 nm, while thickness of active layer of the HIT cell was kept constant, to 500 µm. Single-junction solar cell, formed with the bottom subcell had open circuit voltage (V oc) of 705.1 mV, short circuit current density (J sc) of 28.22 mA cm‑2, fill factor (FF) of 0.82 and efficiency of 16.4% under AM1.5G insolation. A relatively low thickness (150 nm) of the perovskite absorber layer was found optimum for the top-subcell to achieve best efficiency of the tandem cell, partly because of intermediate reflection at the interface between the two cells. We obtained a maximum of 20.92% efficiency of the tandem solar cell, which is higher by a factor of 1.27 from the starting HIT cell and a factor 1.47 higher from the perovskite cell efficiency. J sc of the optimized tandem cell was 13.06 mA cm‑2. This was achieved near the matching optical absorption or current-density of the component subcells. For a practical application, the device used in our investigation was without textured front surface. An ordinary HIT bottom-cell was used with lower J sc. Therefore, with an improved HIT subcell, efficiency of the tandem cell, higher than 21% will be achievable.

  18. Localized Spectroscopy from Anatomically Matched Compartments: Improved Sensitivity and Localization for Cardiac 31P MRS in Humans

    NASA Astrophysics Data System (ADS)

    Löffler, Ralf; Sauter, Rolf; Kolem, Heinrich; Haase, Axel; von Kienlin, Markus

    1998-10-01

    Several pioneering studies have demonstrated that localized31P NMR spectroscopy of the human heart might become an important diagnostic tool in cardiology. The main limitation is due to the low sensitivity of these experiments, allowing only crude spatial resolution. We have implemented a three-dimensional version of SLOOP ("spectral localization with optimal pointspread function") on a clinical instrument. SLOOP takes advantage of all availablea prioriinformation to match the size and the shape of the sensitive volumes to the anatomical structures in the examined subject. Thus, SLOOP reduces the contamination from adjacent organs and improves the sensitivity compared to conventional techniques such as ISIS or chemical shift imaging (CSI). Initial studies were performed on six healthy volunteers at 1.5 T. The good localization properties are demonstrated by the absence of resonances from blood in the heart spectra, and by PCr-free spectra from the liver. Compared to conventional CSI, the signal-to-noise ratio of the SLOOP heart spectra was improved by approximately 30%. Taking into account the varying excitation angle in the inhomogeneous B1field of the surface coil, the SLOOP model computes the local spin saturation at every point in space. Therefore, no global saturation correction is required in the quantitative evaluation of local spectra. In this study, we found a PCr/γ-ATP ratio in the left ventricular wall of 1.90 ± 0.33 (mean ± standard deviation).

  19. Non-matrix Matched Glass Disk Calibration Standards Improve XRF Micronutrient Analysis of Wheat Grain across Five Laboratories in India.

    PubMed

    Guild, Georgia E; Stangoulis, James C R

    2016-01-01

    Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program.

  20. Non-matrix Matched Glass Disk Calibration Standards Improve XRF Micronutrient Analysis of Wheat Grain across Five Laboratories in India

    PubMed Central

    Guild, Georgia E.; Stangoulis, James C. R.

    2016-01-01

    Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program. PMID:27375644

  1. Improved Body Mass Index Measures Following a Middle School-Based Obesity Intervention--The MATCH Program

    ERIC Educational Resources Information Center

    Lazorick, Suzanne; Fang, Xiangming; Hardison, George T.; Crawford, Yancey

    2015-01-01

    Background: Motivating Adolescents with Technology to CHOOSE Health™ (MATCH) is an educational and behavioral intervention in seventh grade. Methods: Teachers in 2 schools delivered the MATCH curriculum, with 1 control school. Using a quasi-experimental design, outcome measures included lessons completed, body mass index (BMI), BMI z-score (zBMI),…

  2. Improved Body Mass Index Measures Following a Middle School-Based Obesity Intervention--The MATCH Program

    ERIC Educational Resources Information Center

    Lazorick, Suzanne; Fang, Xiangming; Hardison, George T.; Crawford, Yancey

    2015-01-01

    Background: Motivating Adolescents with Technology to CHOOSE Health™ (MATCH) is an educational and behavioral intervention in seventh grade. Methods: Teachers in 2 schools delivered the MATCH curriculum, with 1 control school. Using a quasi-experimental design, outcome measures included lessons completed, body mass index (BMI), BMI z-score (zBMI),…

  3. Perfect anti-reflection from first principles

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Ho; Q-Han Park

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies.

  4. Perfect anti-reflection from first principles

    PubMed Central

    Kim, Kyoung-Ho; Q-Han Park

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies. PMID:23320143

  5. Perfect anti-reflection from first principles.

    PubMed

    Kim, Kyoung-Ho; Park, Q-Han

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies.

  6. Matching Theory - A Sampler: From Denes Koenig to the Present

    DTIC Science & Technology

    1991-01-01

    gives a polynomial algorithm for the number of perfect match- .mgs in a planar graph 1964-65 Gallai and Edmonds obtain canonical decomposition for any...graph in terms of its naxirnum matchings 1965 Edmonds develops first polynomial matching algorithm for non-ipartite graphs 196 Erd~s and RInyi...1959-60), begins an as yet incomplete extension of the structure of graphs with a perfect matching 1979 Khachian develops first polynomial algorithm

  7. The Perfective Past Tense in Greek Adolescents with Down Syndrome

    ERIC Educational Resources Information Center

    Stathopoulou, Nikolitsa; Clahsen, Harald

    2010-01-01

    This study investigates the ability of a group of eight Greek-speaking adolescents with Down Syndrome (DS) (aged 12.1-18.7) to handle the perfective past tense using an acceptability judgement task. The performance of the DS participants was compared with that of 16 typically-developing children whose chronological age was matched with the mental…

  8. Multi-domain computerized cognitive training program improves performance of bookkeeping tasks: a matched-sampling active-controlled trial

    PubMed Central

    Lampit, Amit; Ebster, Claus; Valenzuela, Michael

    2014-01-01

    Cognitive skills are important predictors of job performance, but the extent to which computerized cognitive training (CCT) can improve job performance in healthy adults is unclear. We report, for the first time, that a CCT program aimed at attention, memory, reasoning and visuo-spatial abilities can enhance productivity in healthy younger adults on bookkeeping tasks with high relevance to real-world job performance. 44 business students (77.3% female, mean age 21.4 ± 2.6 years) were assigned to either (a) 20 h of CCT, or (b) 20 h of computerized arithmetic training (active control) by a matched sampling procedure. Both interventions were conducted over a period of 6 weeks, 3–4 1-h sessions per week. Transfer of skills to performance on a 60-min paper-based bookkeeping task was measured at three time points—baseline, after 10 h and after 20 h of training. Repeated measures ANOVA found a significant Group X Time effect on productivity (F = 7.033, df = 1.745; 73.273, p = 0.003) with a significant interaction at both the 10-h (Relative Cohen's effect size = 0.38, p = 0.014) and 20-h time points (Relative Cohen's effect size = 0.40, p = 0.003). No significant effects were found on accuracy or on Conners' Continuous Performance Test, a measure of sustained attention. The results are discussed in reference to previous findings on the relationship between brain plasticity and job performance. Generalization of results requires further study. PMID:25120510

  9. Prior Bariatric Surgery Is Linked to Improved Colorectal Cancer Surgery Outcomes and Costs: A Propensity-Matched Analysis.

    PubMed

    Hussan, Hisham; Stanich, Peter P; Gray, Darrell M; Krishna, Somashekar G; Porter, Kyle; Conwell, Darwin L; Clinton, Steven K

    2017-04-01

    Morbid obesity is associated with worse colorectal cancer (CRC) perioperative outcomes. The impact of bariatric surgery on these outcomes is unknown. The National Inpatient Sample Database (2006-2012) was used to identify adults with prior bariatric surgery (divided into BMI ≤35 kg/m(2) and BMI >35 kg/m(2)) or morbid obesity that underwent CRC surgery. Main outcomes were mortality, surgical complications and health care utilization. There were 1813 patients with prior bariatric surgery and 22,552 morbidly obese patients that underwent CRC surgery between 2006 and 2012. Prior bariatric surgery patients were younger, with fewer comorbidities, and had less emergency CRC surgery admissions (p < 0.05). Multivariate analyses revealed no adverse association (OR 0.54, 95 % CI = 0.16 to 1.79) between prior bariatric surgery and CRC perioperative mortality. Notably, multivariate analysis revealed that bariatric surgery patients undergoing CRC surgery had fewer accidental surgical lacerations (OR 0.38, 95 % CI = 0.15 to 0.93), shorter hospitalizations (-1.85 days, 95 % CI = 2.03 to 1.67), decreased total hospital costs (US$-5374, 95 % CI = -5935 to -4813) and lower disposition to short-term rehabilitation facilities (OR 0.65, 95 % CI = -0.43 to 0.97). Propensity score matched analysis validated these reductions in surgical complications and health care utilization in bariatric surgery patients, which were further more pronounced when bariatric surgery patients were restricted to BMI ≤35 kg/m(2). Analysis of national-level data demonstrates that prior bariatric surgery is associated with fewer colorectal cancer surgical complications and improved health care resource utilization compared to morbidly obese patients. These findings emphasize and extend the therapeutic effect of bariatric surgery to the colorectal cancer perioperative setting.

  10. Numerical study of an ultra-broadband near-perfect solar absorber in the visible and near-infrared region.

    PubMed

    Wu, Dong; Liu, Chang; Liu, Yumin; Yu, Li; Yu, Zhongyuan; Chen, Lei; Ma, Rui; Ye, Han

    2017-02-01

    We propose and numerically investigate a novel ultra-broadband solar absorber by applying iron in a 2D simple metamaterial structure. The proposed structure can achieve the perfect absorption above 95% covering the wavelength range from 400 to 1500 nm. The average absorption reaches 97.8% over this wavelength range. The broadband perfect absorption is caused by the excitation of localized surface plasmon resonance and propagating surface plasmon resonance. We first propose and demonstrate that the iron is obviously beneficial to achieve impedance matching between the metamaterial structure and the free space over an ultra-broad frequency band in the visible and near-infrared region, which play an extremely important role to generate an ultra-broadband perfect absorption. In order to further broaden the absorption band, we also demonstrate the perfect absorption exceeding 92% for the 400-2000 nm range by adding the number of metal-dielectric pairs and using both gold and iron simultaneously in the proposed structure. The average absorption of the improved absorber reaches 96.4% over the range of 400-2000 nm. The metamaterial absorbers using iron are very promising for many applications, which can greatly broaden the perfect absorption band in the solar spectrum and, meanwhile, can enormously reduce the cost in the actual production.

  11. Improvement of the matching speed of AIMS for development of an automatic totally tuning system for hyperthermia treatment using a resonant cavity applicator.

    PubMed

    Shindo, Y; Kato, K; Tsuchiya, K; Hirashima, T; Suzuki, M

    2009-01-01

    In this paper, we discuss the improvement of the speed of AIMS (Automatic Impedance Matching System) to automatically make impedance matching for a re-entrant resonant cavity applicator for non-invasive deep brain tumors hyperthermia treatments. We have already discussed the effectiveness of the heating method using the AIMS, with experiments of heating agar phantoms. However, the operating time of AIMS was about 30 minutes. To develop the ATT System (Automatic Totally Tuning System) including the automatic frequency tuning system, we must improve this problem. Because, when using the ATTS, the AIMS is used repeatedly to find the resonant frequency. In order to improve the speed of impedance matching, we developed the new automatic impedance matching system program (AIMS2). In AIMS, the stepping motors were connected to the impedance matching unit's dials. These dials were turned to reduce the reflected power. AIMS consists of two phases: all range searching and detailed searching. We focused on the three factors affecting the operating speed and improved them. The first factor is the interval put between the turning of the motors and AD converter. The second factor is how the steps of the motor when operating all range searching. The third factor is the starting position of the motor when detail searching. We developed the simple ATT System (ATT-beta) based on the AIMS2. To evaluate the developed AIMS2 and ATT- beta, experiments with an agar phantom were performed. From these results, we found that the operating time of the AIMS2 is about 4 minutes, which was approximately 12% of AIMS. From ATT-beta results, it was shown that it is possible to tune frequency and automatically match impedance with the program based on the AIMS2.

  12. Searching for an Improved Spectral Match to TES and IRIS Sinus Meridiani Spectra: Coatings and Cemented Materials

    NASA Astrophysics Data System (ADS)

    Kirkland, L. E.; Herr, K. C.; Adams, P. M.

    2001-05-01

    A region on Mars within Sinus Meridiani has been interpreted as a surface partially covered by coarse-grained (gray) hematite, using spectra measured by the 1996 Global Surveyor Thermal Emission Spectrometer (TES) [Lane et al., 1999; Christensen et al., 2000]. The band strengths recorded by TES of this region are consistent with either coarse-grained hematite, or cemented poorly crystalline or cemented fine-grained hematite. The band strengths are inconsistent with unconsolidated, poorly crystalline or fine-grained hematite, including nanophase hematite dust [Christensen et al., 2000]. Currently the gray hematite interpretation is based on bands centered near 22 and 33 microns. TES also records a band centered near 18 microns that was used in early hematite interpretations [Lane et al., 1999]. However, it was noted [Kirkland et al., 1999a] that the 18 micron band is too narrow in both TES and the 1971 Mariner Mars IRIS spectra to be a good match to typical spectra of well-crystalline hematite [e.g. Salisbury et al., 1991]. The 18 micron band is near the very strong 15 micron atmospheric CO2 band, but if anything the nearby CO2 band should cause the 18 micron band to appear wider, not narrower. In addition, the higher spectral resolution of IRIS allows improved separation of the bands [Kirkland et al., 1999b]. More recent publications no longer show the TES 18 micron band [e.g. Lane et al., 2000; Christensen et al., 2000], which temporarily resolved the issue. However, we feel it is important to understand why TES and IRIS spectra exhibit an 18 micron band that is too narrow to match typical spectra of coarse-grained hematite. Smooth-surfaced cemented (e.g. ferricrete) or coated materials (e.g. desert varnish) have spectral contrast that is consistent with the observed IRIS and TES band contrast. On Mars, one possible source for cemented material or coatings would be the nanophase hematite dust. Cemented materials may occur in bulk (e.g. duricrust or ferricrete), or

  13. Matching Procedures at the Time of Immediate Breast Reconstruction: An American College of Surgeons National Surgical Quality Improvement Program Study of 24,191 Patients.

    PubMed

    Cooney, Carisa M; Sebai, Mohamad E; Ogbuagu, Onyebuchi; Devulapalli, Chris; Manahan, Michele A; Rosson, Gedge D

    2016-12-01

    The purpose of this study was to assess for compounded risk of postoperative morbidity with the addition of a simultaneous contralateral breast matching procedure at the time of mastectomy and immediate breast reconstruction. 2005 to 2012 American College of Surgeons National Surgical Quality Improvement Program databases were used to identify cases of mastectomy and immediate breast reconstruction with and without simultaneous contralateral breast matching procedures. Matching procedures included mastopexy, reduction mammaplasty, and augmentation mammaplasty. Thirty-day postoperative morbidity was assessed using univariable and multivariable logistic regression. Of 59,766 mastectomy patients, 24,191 (40 percent) underwent immediate breast reconstruction: 903 (3.7 percent) underwent matching procedures and 23,288 (96.3 percent) did not. Univariable logistic regression demonstrated that the matching procedure group had statistically significantly higher overall morbidity (OR, 1.288; 95 percent CI, 1.022 to 1.623; p = 0.032). Although surgical and systemic morbidity did not differ significantly, the matching procedure group demonstrated higher risk for superficial surgical-site infection (OR, 1.57; 95 percent CI, 1.066 to 2.31; p = 0.022), reconstruction failure (OR, 1.69; 95 percent CI, 1.014 to 2.814; p = 0.044), and pulmonary embolism (OR, 2.54; 95 percent CI, 1.01 to 6.37; p = 0.048). Controlling for possible confounders, multivariable logistic regression rendered the relationship between matching procedure and complications insignificant (OR, 1.17; 95 percent CI, 0.92 to 1.48; p = 0.2). These data suggest that preoperative comorbidities and other patient-related factors may have a larger influence on postoperative morbidity than the addition of a contralateral matching procedure alone. Therapeutic, III.

  14. The Perfect Science Machine

    NASA Astrophysics Data System (ADS)

    2008-05-01

    ESO celebrates 10 years since First Light of the VLT Today marks the 10th anniversary since First Light with ESO's Very Large Telescope (VLT), the most advanced optical telescope in the world. Since then, the VLT has evolved into a unique suite of four 8.2-m Unit Telescopes (UTs) equipped with no fewer than 13 state-of-the-art instruments, and four 1.8-m moveable Auxiliary Telescopes (ATs). The telescopes can work individually, and they can also be linked together in groups of two or three to form a giant 'interferometer' (VLTI), allowing astronomers to see details corresponding to those from a much larger telescope. Green Flash at Paranal ESO PR Photo 16a/08 The VLT 10th anniversary poster "The Very Large Telescope array is a flagship facility for astronomy, a perfect science machine of which Europe can be very proud," says Tim de Zeeuw, ESO's Director General. "We have built the most advanced ground-based optical observatory in the world, thanks to the combination of a long-term adequately-funded instrument and technology development plan with an approach where most of the instruments were built in collaboration with institutions in the member states, with in-kind contributions in labour compensated by guaranteed observing time." Sitting atop the 2600m high Paranal Mountain in the Chilean Atacama Desert, the VLT's design, suite of instruments, and operating principles set the standard for ground-based astronomy. It provides the European scientific community with a telescope array with collecting power significantly greater than any other facilities available at present, offering imaging and spectroscopy capabilities at visible and infrared wavelengths. Blue Flash at Paranal ESO PR Photo 16b/08 A Universe of Discoveries The first scientifically useful images, marking the official 'First Light' of the VLT, were obtained on the night of 25 to 26 May 1998, with a test camera attached to "Antu", Unit Telescope number 1. They were officially presented to the press on

  15. Brachytherapy Improves Biochemical Failure–Free Survival in Low- and Intermediate-Risk Prostate Cancer Compared With Conventionally Fractionated External Beam Radiation Therapy: A Propensity Score Matched Analysis

    SciTech Connect

    Smith, Graham D.; Pickles, Tom; Crook, Juanita; Martin, Andre-Guy; Vigneault, Eric; Cury, Fabio L.; Morris, Jim; Catton, Charles; Lukka, Himu; Warner, Andrew; Yang, Ying; Rodrigues, George

    2015-03-01

    Purpose: To compare, in a retrospective study, biochemical failure-free survival (bFFS) and overall survival (OS) in low-risk and intermediate-risk prostate cancer patients who received brachytherapy (BT) (either low-dose-rate brachytherapy [LDR-BT] or high-dose-rate brachytherapy with external beam radiation therapy [HDR-BT+EBRT]) versus external beam radiation therapy (EBRT) alone. Methods and Materials: Patient data were obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated with primary radiation therapy at four Canadian cancer institutions from 1994 to 2010. Propensity score matching was used to obtain the following 3 matched cohorts with balanced baseline prognostic factors: (1) low-risk LDR-BT versus EBRT; (2) intermediate-risk LDR-BT versus EBRT; and (3) intermediate-risk HDR-BT+EBRT versus EBRT. Kaplan-Meier survival analysis was performed to compare differences in bFFS (primary endpoint) and OS in the 3 matched groups. Results: Propensity score matching created acceptable balance in the baseline prognostic factors in all matches. Final matches included 2 1:1 matches in the intermediate-risk cohorts, LDR-BT versus EBRT (total n=254) and HDR-BT+EBRT versus EBRT (total n=388), and one 4:1 match in the low-risk cohort (LDR-BT:EBRT, total n=400). Median follow-up ranged from 2.7 to 7.3 years for the 3 matched cohorts. Kaplan-Meier survival analysis showed that all BT treatment options were associated with statistically significant improvements in bFFS when compared with EBRT in all cohorts (intermediate-risk EBRT vs LDR-BT hazard ratio [HR] 4.58, P=.001; intermediate-risk EBRT vs HDR-BT+EBRT HR 2.08, P=.007; low-risk EBRT vs LDR-BT HR 2.90, P=.004). No significant difference in OS was found in all comparisons (intermediate-risk EBRT vs LDR-BT HR 1.27, P=.687; intermediate-risk EBRT vs HDR-BT+EBRT HR 1.55, P=.470; low-risk LDR-BT vs EBRT HR 1.41, P=.500). Conclusions: Propensity score matched analysis showed that BT options led

  16. Does Short-Duration Heat Exposure at a Matched Cardiovascular Intensity Improve Intermittent-Running Performance in a Cool Environment?

    PubMed

    Philp, Calvin P; Buchheit, Martin; Kitic, Cecilia M; Minson, Christopher T; Fell, James W

    2017-07-01

    To investigate whether a 5-d cycling training block in the heat (35°C) in Australian Rules footballers was superior to exercising at the same relative intensity in cool conditions (15°C) for improving intermittent-running performance in a cool environment (<18°C). Using a parallel-group design, 12 semiprofessional football players performed 5 d of cycling exercise (70% heart-rate reserve [HRR] for 45 min [5 × 50-min sessions in total]) in a hot (HEAT, 35°C ± 1°C, 56% ± 9% RH) or cool environment (COOL, 15°C ± 3°C, 81% ± 10% RH). A 30-15 Intermittent Fitness Test to assess intermittent running performance (VIFT) was conducted in a cool environment (17°C ± 2°C, 58 ± 5% RH) before and twice after (1 and 3 d) the intervention. There was a likely small increase in VIFT in each group (HEAT, 0.5 ± 0.3 km/h, 1.5 ± 0.8 × smallest worthwhile change [SWC]; COOL, 0.4 ± 0.4 km/h, 1.6 ± 1.2 × SWC) 3 d postintervention, with no difference in change between the groups (0.5% ± 1.9%, 0.4 ± 1.4 × SWC). Cycle power output during the intervention was almost certainly lower in the HEAT group (HEAT 1.8 ± 0.2 W/kg vs COOL 2.5 ± 0.3 W/kg, -21.7 ± 3.2 × SWC, 100/0/0). When cardiovascularexercise intensity is matched (ie, 70% HRR) between environmental conditions, there is no additional performance benefit from short-duration moderate-intensity heat exposure (5 × 50 min) for semiprofessional footballers exercising in cool conditions. However, the similar positive adaptations may occur in HEAT with 30% lower mechanical load, which may be of interest for load management during intense training or rehabilitation phases.

  17. Practice Doesn’t Always Make Perfect: A Qualitative Study Explaining Why a Trial of an Educational Toolkit Did Not Improve Quality of Care

    PubMed Central

    Parsons, Janet A.; Yu, Catherine H. Y.; Baker, Natalie A.; Mamdani, Muhammad M.; Bhattacharyya, Onil; Zwarenstein, Merrick; Shah, Baiju R.

    2016-01-01

    Background Diabetes is a chronic disease commonly managed by family physicians, with the most prevalent complication being cardiovascular disease (CVD). Clinical practice guidelines have been developed to support clinicians in the care of diabetic patients. We conducted a pragmatic cluster randomized controlled trial (RCT) of a printed educational toolkit aimed at improving CVD management in diabetes in primary care, and found no effect, and indeed, the possibility of some harm. We conducted a qualitative evaluation to study the strategy for guideline implementation employed in this trial, and to understand its effects. This paper focuses solely on the qualitative findings, as the RCT’s quantitative results have already been reported elsewhere. Methods and Findings All family practices in the province of Ontario had been randomized to receive the educational toolkit by mail, in either the summer of 2009 (intervention arm) or the spring of 2010 (control arm).A subset of 80 family physicians (representing approximately 10% of the practices randomized and approached, with records on 1,592 randomly selected patients with diabetes at high risk for CVD) then took part in a chart audit and reflective feedback exercise related to their own practice in comparison to the guideline recommendations. They were asked to complete two forms (one pre- and one post-audit) in order to understand their awareness of the guidelines pre-trial, their expectations regarding their individual performance pre-audit, and their reflections on their audit results. In addition, individual interviews with thirteen other family physicians were conducted. Textual data from interview transcripts and written commentary from the pre- and post-audit forms underwent qualitative descriptive analysis to identify common themes and patterns. Analysis revealed four main themes: impressions of the toolkit, awareness was not the issue, ‘it’s not me it’s my patients’, and chart audit as a more

  18. Improving Balance in Regression Discontinuity Design by Matching: Estimating the Effect of Academic Probation after the First Year of College

    ERIC Educational Resources Information Center

    Chi, Olivia L.; Dow, Aaron W.

    2014-01-01

    This study focuses on how matching, a method of preprocessing data prior to estimation and analysis, can be used to reduce imbalance between treatment and control group in regression discontinuity design. To examine the effects of academic probation on student outcomes, researchers replicate and expand upon research conducted by Lindo, Sanders,…

  19. Infrared perfect absorber based on nanowire metamaterial cavities.

    PubMed

    He, Yingran; Deng, Huixu; Jiao, Xiangyang; He, Sailing; Gao, Jie; Yang, Xiaodong

    2013-04-01

    An infrared perfect absorber based on a gold nanowire metamaterial cavities array on a gold ground plane is designed. The metamaterial made of gold nanowires embedded in an alumina host exhibits an effective permittivity with strong anisotropy, which supports cavity resonant modes of both electric dipole and magnetic dipole. The impedance of the cavity modes matches the incident plane wave in free space, leading to nearly perfect light absorption. The incident optical energy is efficiently converted into heat so that the local temperature of the absorber will increase. Results show that the designed absorber is polarization-insensitive and nearly omnidirectional for the incident angle.

  20. Magnetically tunable metamaterial perfect absorber

    NASA Astrophysics Data System (ADS)

    Lei, Ming; Feng, Ningyue; Wang, Qingmin; Hao, Yanan; Huang, Shanguo; Bi, Ke

    2016-06-01

    A magnetically tunable metamaterial perfect absorber (MPA) based on ferromagnetic resonance is experimentally and numerically demonstrated. The ferrite-based MPA is composed of an array of ferrite rods and a metallic ground plane. Frequency dependent absorption of the ferrite-based MPA under a series of applied magnetic fields is discussed. An absorption peak induced by ferromagnetic resonance appears in the range of 8-12 GHz under a certain magnetic field. Both the simulated and experimental results demonstrate that the absorption frequency of the ferrite-based MPA can be tuned by the applied magnetic field. This work provides an effective way to fabricate the magnetically tunable metamaterial perfect absorber.

  1. Factors influencing perfect surgical outcome.

    PubMed

    Lim, A S

    1997-03-01

    With affluence and education, the population of Asia will be demanding quality surgical care. The energetic, affluent and educated Asian professionals and business communities in the cities demand the best; and in surgery, they seek perfect results. Perfect results require a combination of 3 factors: the skill, knowledge and experience of the surgeon. He must be a skilled surgeon with good basic surgical techniques and also technical skills in the management of his discipline combined with meticulous attention to details. Furthermore, he must have a clear knowledge of the basic physiopathology of surgical principles of the condition he is to manage. Experience with difficult situations and intrasurgical problems are essential for success.

  2. Interference theory of metamaterial perfect absorbers.

    PubMed

    Chen, Hou-Tong

    2012-03-26

    The impedance matching to free space in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with direct evidence provided by the anti-parallel surface currents in the metal structures. Here I present a different theoretical interpretation based on interference, which shows that the two layers of metal structures in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

  3. Experimental realization of coherent perfect polarization rotation.

    PubMed

    Zhou, Chuanhong; Andrews, James H; Crescimanno, Michael

    2016-05-15

    Coherent perfect processes enable high optical efficiencies in optical conversion phenomena such as coherent perfect absorption or coherent perfect polarization rotation. A linear optical coherent perfect process based on Faraday rotation has been evaluated experimentally, achieving contrast limited by other optical components of the system and demonstrating like-parity resonance doublets above threshold.

  4. Perfect vortex beam: Fourier transformation of a Bessel beam.

    PubMed

    Vaity, Pravin; Rusch, Leslie

    2015-02-15

    We derive a mathematical description of a perfect vortex beam as the Fourier transformation of a Bessel beam. Building on this development, we experimentally generate Bessel-Gauss beams of different orders and Fourier transform them to form perfect vortex beams. By controlling the radial wave vector of a Bessel-Gauss beam, we can control the ring radius of the generated beam. Our theoretical predictions match with the experimental results and also provide an explanation for previous published works. We find the perfect vortex resembles that of an orbital angular momentum (OAM) mode supported in annular profiled waveguides. Our prefect vortex beam generation method can be used to excite OAM modes in an annular core fiber.

  5. IMPROVED MOCK GALAXY CATALOGS FOR THE DEEP2 GALAXY REDSHIFT SURVEY FROM SUBHALO ABUNDANCE AND ENVIRONMENT MATCHING

    SciTech Connect

    Gerke, Brian F.; Wechsler, Risa H.; Behroozi, Peter S.; Yan, Renbin; Coil, Alison L.

    2013-09-15

    We develop empirical methods for modeling the galaxy population and populating cosmological N-body simulations with mock galaxies according to the observed properties of galaxies in survey data. We use these techniques to produce a new set of mock catalogs for the DEEP2 Galaxy Redshift Survey based on the output of the high-resolution Bolshoi simulation, as well as two other simulations with different cosmological parameters, all of which we release for public use. The mock-catalog creation technique uses subhalo abundance matching to assign galaxy luminosities to simulated dark-matter halos. It then adds color information to the resulting mock galaxies in a manner that depends on the local galaxy density, in order to reproduce the measured color-environment relation in the data. In the course of constructing the catalogs, we test various models for including scatter in the relation between halo mass and galaxy luminosity, within the abundance-matching framework. We find that there is no constant-scatter model that can simultaneously reproduce both the luminosity function and the autocorrelation function of DEEP2. This result has implications for galaxy-formation theory, and it restricts the range of contexts in which the mock catalogs can be usefully applied. Nevertheless, careful comparisons show that our new mock catalogs accurately reproduce a wide range of the other properties of the DEEP2 catalog, suggesting that they can be used to gain a detailed understanding of various selection effects in DEEP2.

  6. A perfect launch on a perfect Florida day!

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A perfect launch on a perfect Florida day! Framed by two immense billows of steam, Space Shuttle Endeavour breaks its Earthly tethers to soar into a clear blue sky. Liftoff of mission STS-99 occurred at 12:43:40 p.m. EST. Known as the Shuttle Radar Topography Mission (SRTM), STS-99 will chart a new course to produce unrivaled 3-D images of the Earth's surface. The result of the SRTM could be close to 1 trillion measurements of the Earth's topography. The mission is expected to last 11days, with Endeavour landing at KSC Tuesday, Feb. 22, at 4:36 p.m. EST. This is the 97th Shuttle flight and 14th for Shuttle Endeavour.

  7. A perfect launch on a perfect Florida day!

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A perfect launch on a perfect Florida day! Space Shuttle Endeavour, with its crew of five, scatters billows of steam and smoke as it lifts off at 12:43:40 p.m. EST on mission STS-99. Employees and visitors watch intently from across the turn basin. Known as the Shuttle Radar Topography Mission (SRTM), STS-99 will chart a new course to produce unrivaled 3-D images of the Earth's surface. The result of the SRTM could be close to 1 trillion measurements of the Earth's topography. The mission is expected to last 11days, with Endeavour landing at KSC Tuesday, Feb. 22, at 4:36 p.m. EST. This is the 97th Shuttle flight and 14th for Shuttle Endeavour.

  8. "Perfect" designer chromosome V and behavior of a ring derivative.

    PubMed

    Xie, Ze-Xiong; Li, Bing-Zhi; Mitchell, Leslie A; Wu, Yi; Qi, Xin; Jin, Zhu; Jia, Bin; Wang, Xia; Zeng, Bo-Xuan; Liu, Hui-Min; Wu, Xiao-Le; Feng, Qi; Zhang, Wen-Zheng; Liu, Wei; Ding, Ming-Zhu; Li, Xia; Zhao, Guang-Rong; Qiao, Jian-Jun; Cheng, Jing-Sheng; Zhao, Meng; Kuang, Zheng; Wang, Xuya; Martin, J Andrew; Stracquadanio, Giovanni; Yang, Kun; Bai, Xue; Zhao, Juan; Hu, Meng-Long; Lin, Qiu-Hui; Zhang, Wen-Qian; Shen, Ming-Hua; Chen, Si; Su, Wan; Wang, En-Xu; Guo, Rui; Zhai, Fang; Guo, Xue-Jiao; Du, Hao-Xing; Zhu, Jia-Qing; Song, Tian-Qing; Dai, Jun-Jun; Li, Fei-Fei; Jiang, Guo-Zhen; Han, Shi-Lei; Liu, Shi-Yang; Yu, Zhi-Chao; Yang, Xiao-Na; Chen, Ken; Hu, Cheng; Li, Da-Shuai; Jia, Nan; Liu, Yue; Wang, Lin-Ting; Wang, Su; Wei, Xiao-Tong; Fu, Mei-Qing; Qu, Lan-Meng; Xin, Si-Yu; Liu, Ting; Tian, Kai-Ren; Li, Xue-Nan; Zhang, Jin-Hua; Song, Li-Xiang; Liu, Jin-Gui; Lv, Jia-Fei; Xu, Hang; Tao, Ran; Wang, Yan; Zhang, Ting-Ting; Deng, Ye-Xuan; Wang, Yi-Ran; Li, Ting; Ye, Guang-Xin; Xu, Xiao-Ran; Xia, Zheng-Bao; Zhang, Wei; Yang, Shi-Lan; Liu, Yi-Lin; Ding, Wen-Qi; Liu, Zhen-Ning; Zhu, Jun-Qi; Liu, Ning-Zhi; Walker, Roy; Luo, Yisha; Wang, Yun; Shen, Yue; Yang, Huanming; Cai, Yizhi; Ma, Ping-Sheng; Zhang, Chun-Ting; Bader, Joel S; Boeke, Jef D; Yuan, Ying-Jin

    2017-03-10

    Perfect matching of an assembled physical sequence to a specified designed sequence is crucial to verify design principles in genome synthesis. We designed and de novo synthesized 536,024-base pair chromosome synV in the "Build-A-Genome China" course. We corrected an initial isolate of synV to perfectly match the designed sequence using integrative cotransformation and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated editing in 22 steps; synV strains exhibit high fitness under a variety of culture conditions, compared with that of wild-type V strains. A ring synV derivative was constructed, which is fully functional in Saccharomyces cerevisiae under all conditions tested and exhibits lower spore viability during meiosis. Ring synV chromosome can extends Sc2.0 design principles and provides a model with which to study genomic rearrangement, ring chromosome evolution, and human ring chromosome disorders.

  9. Perfect-fluid sources for the Levi-Civita metric

    NASA Astrophysics Data System (ADS)

    Ali, Ramadan M.

    2007-08-01

    Cylindrically symmetric perfect fluid solutions are derived for the Levi-Civita metric. The pressure P is finite. The matter density is greater than the stresses in the material. The solutions are inside cylinders of bounded radius at which the pressure vanishes. The range of σ, for which the sources have been matched to the Levi-Civeta metric is ∞> σ>0. The solutions are regular and satisfy energy conditions

  10. Effective perfect fluids in cosmology

    SciTech Connect

    Ballesteros, Guillermo; Bellazzini, Brando E-mail: brando.bellazzini@pd.infn.it

    2013-04-01

    We describe the cosmological dynamics of perfect fluids within the framework of effective field theories. The effective action is a derivative expansion whose terms are selected by the symmetry requirements on the relevant long-distance degrees of freedom, which are identified with comoving coordinates. The perfect fluid is defined by requiring invariance of the action under internal volume-preserving diffeomorphisms and general covariance. At lowest order in derivatives, the dynamics is encoded in a single function of the entropy density that characterizes the properties of the fluid, such as the equation of state and the speed of sound. This framework allows a neat simultaneous description of fluid and metric perturbations. Longitudinal fluid perturbations are closely related to the adiabatic modes, while the transverse modes mix with vector metric perturbations as a consequence of vorticity conservation. This formalism features a large flexibility which can be of practical use for higher order perturbation theory and cosmological parameter estimation.

  11. Visible light broadband perfect absorbers

    SciTech Connect

    Jia, X. L.; Meng, Q. X.; Yuan, C. X.; Zhou, Z. X.; Wang, X. O.

    2016-03-15

    The visible light broadband perfect absorbers based on the silver (Ag) nano elliptical disks and holes array are studied using finite difference time domain simulations. The semiconducting indium silicon dioxide thin film is introduced as the space layer in this sandwiched structure. Utilizing the asymmetrical geometry of the structures, polarization sensitivity for transverse electric wave (TE)/transverse magnetic wave (TM) and left circular polarization wave (LCP)/right circular polarization wave (RCP) of the broadband absorption are gained. The absorbers with Ag nano disks and holes array show several peaks absorbance of 100% by numerical simulation. These simple and flexible perfect absorbers are particularly desirable for various potential applications including the solar energy absorber.

  12. Matched-pair classification

    SciTech Connect

    Theiler, James P

    2009-01-01

    Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.

  13. Prematurely Delivered Rats Show Improved Motor Coordination During Sensory-evoked Motor Responses Compared to Age-matched Controls

    PubMed Central

    Roberto, Megan E.; Brumley, Michele R.

    2014-01-01

    The amount of postnatal experience for perinatal rats was manipulated by delivering pups one day early (postconception day 21; PC21) by cesarean delivery and comparing their motor behavior to age-matched controls on PC22 (the typical day of birth). On PC22, pups were tested on multiple measures of motor coordination: leg extension response (LER), facial wiping, contact righting, and fore- and hindlimb stepping. The LER and facial wiping provided measures of synchronous hind- and forelimb coordination, respectively, and were sensory-evoked. Contact righting also was sensory-evoked and provided a measure of axial coordination. Stepping provided a measure of alternated forelimb and hindlimb coordination and was induced with the serotonin receptor agonist quipazine. Pups that were delivered prematurely and spent an additional day in the postnatal environment showed more bilateral limb coordination during expression of the LER and facial wiping, as well as a more mature righting strategy, compared to controls. These findings suggest that experience around the time of birth shapes motor coordination and the expression of species-typical behavior in the developing rat. PMID:24680729

  14. Prematurely delivered rats show improved motor coordination during sensory-evoked motor responses compared to age-matched controls.

    PubMed

    Roberto, Megan E; Brumley, Michele R

    2014-05-10

    The amount of postnatal experience for perinatal rats was manipulated by delivering pups one day early (postconception day 21; PC21) by cesarean delivery and comparing their motor behavior to age-matched controls on PC22 (the typical day of birth). On PC22, pups were tested on multiple measures of motor coordination: leg extension response (LER), facial wiping, contact righting, and fore- and hindlimb stepping. The LER and facial wiping provided measures of synchronous hind- and forelimb coordination, respectively, and were sensory-evoked. Contact righting also was sensory-evoked and provided a measure of axial coordination. Stepping provided a measure of alternated forelimb and hindlimb coordination and was induced with the serotonin receptor agonist quipazine. Pups that were delivered prematurely and spent an additional day in the postnatal environment showed more bilateral limb coordination during expression of the LER and facial wiping, as well as a more mature righting strategy, compared to controls. These findings suggest that experience around the time of birth shapes motor coordination and the expression of species-typical behavior in the developing rat.

  15. A New Minimum Trees-Based Approach for Shape Matching with Improved Time Computing: Application to Graphical Symbols Recognition

    NASA Astrophysics Data System (ADS)

    Franco, Patrick; Ogier, Jean-Marc; Loonis, Pierre; Mullot, Rémy

    Recently we have developed a model for shape description and matching. Based on minimum spanning trees construction and specifics stages like the mixture, it seems to have many desirable properties. Recognition invariance in front shift, rotated and noisy shape was checked through median scale tests related to GREC symbol reference database. Even if extracting the topology of a shape by mapping the shortest path connecting all the pixels seems to be powerful, the construction of graph induces an expensive algorithmic cost. In this article we discuss on the ways to reduce time computing. An alternative solution based on image compression concepts is provided and evaluated. The model no longer operates in the image space but in a compact space, namely the Discrete Cosine space. The use of block discrete cosine transform is discussed and justified. The experimental results led on the GREC2003 database show that the proposed method is characterized by a good discrimination power, a real robustness to noise with an acceptable time computing.

  16. Latent fingerprint matching.

    PubMed

    Jain, Anil K; Feng, Jianjiang

    2011-01-01

    Latent fingerprint identification is of critical importance to law enforcement agencies in identifying suspects: Latent fingerprints are inadvertent impressions left by fingers on surfaces of objects. While tremendous progress has been made in plain and rolled fingerprint matching, latent fingerprint matching continues to be a difficult problem. Poor quality of ridge impressions, small finger area, and large nonlinear distortion are the main difficulties in latent fingerprint matching compared to plain or rolled fingerprint matching. We propose a system for matching latent fingerprints found at crime scenes to rolled fingerprints enrolled in law enforcement databases. In addition to minutiae, we also use extended features, including singularity, ridge quality map, ridge flow map, ridge wavelength map, and skeleton. We tested our system by matching 258 latents in the NIST SD27 database against a background database of 29,257 rolled fingerprints obtained by combining the NIST SD4, SD14, and SD27 databases. The minutiae-based baseline rank-1 identification rate of 34.9 percent was improved to 74 percent when extended features were used. In order to evaluate the relative importance of each extended feature, these features were incrementally used in the order of their cost in marking by latent experts. The experimental results indicate that singularity, ridge quality map, and ridge flow map are the most effective features in improving the matching accuracy.

  17. Phenomenological study of the interplay between IR-improved DGLAP-CS theory and the precision of an NLO ME matched parton shower MC

    SciTech Connect

    Majhi, S.K.; Mukhopadhyay, A.; Ward, B.F.L.; Yost, S.A.

    2014-11-15

    We present a phenomenological study of the current status of the application of our approach of exact amplitude-based resummation in quantum field theory to precision QCD calculations, by realistic MC event generator methods, as needed for precision LHC physics. We discuss recent results as they relate to the interplay of the attendant IR-improved DGLAP-CS theory of one of us and the precision of exact NLO matrix-element matched parton shower MC’s in the Herwig6.5 environment as determined by comparison to recent LHC experimental observations on single heavy gauge boson production and decay. The level of agreement between the new theory and the data continues to be a reason for optimism. In the spirit of completeness, we discuss as well other approaches to the same theoretical predictions that we make here from the standpoint of physical precision with an eye toward the (sub-)1% QCD⊗EW total theoretical precision regime for LHC physics. - Highlights: • Using LHC data, we show that IR-improved DGLAP-CS kernels with exact NLO Shower/ME matching improves MC precision. • We discuss other possible approaches in comparison with ours. • We propose experimental tests to discriminate between competing approaches.

  18. SU-E-J-108: Template Matching Based On Multiple Templates Can Improve the Tumor Tracking Performance When There Is Large Tumor Deformation

    SciTech Connect

    Shi, X; Lin, J; Diwanji, T; Mooney, K; D'Souza, W; Mistry, N

    2014-06-01

    Purpose: Recently, template matching has been shown to be able to track tumor motion on cine-MRI images. However, artifacts such as deformation, rotation, and/or out-of-plane movement could seriously degrade the performance of this technique. In this work, we demonstrate the utility of multiple templates derived from different phases of tumor motion in reducing the negative effects of artifacts and improving the accuracy of template matching methods. Methods: Data from 2 patients with large tumors and significant tumor deformation were analyzed from a group of 12 patients from an earlier study. Cine-MRI (200 frames) imaging was performed while the patients were instructed to breathe normally. Ground truth tumor position was established on each frame manually by a radiation oncologist. Tumor positions were also automatically determined using template matching with either single or multiple (5) templates. The tracking errors, defined as the absolute differences in tumor positions determined by the manual and automated methods, when using either single or multiple templates were compared in both the AP and SI directions, respectively. Results: Using multiple templates reduced the tracking error of template matching. In the SI direction where the tumor movement and deformation were significant, the mean tracking error decreased from 1.94 mm to 0.91 mm (Patient 1) and from 6.61 mm to 2.06 mm (Patient 2). In the AP direction where the tumor movement was small, the reduction of the mean tracking error was significant in Patient 1 (from 3.36 mm to 1.04 mm), but not in Patient 2 ( from 3.86 mm to 3.80 mm). Conclusion: This study shows the effectiveness of using multiple templates in improving the performance of template matching when artifacts like large tumor deformation or out-of-plane motion exists. Accurate tumor tracking capabilities can be integrated with MRI guided radiation therapy systems. This work was supported in part by grants from NIH/NCI CA 124766 and Varian

  19. Sildenafil improves microvascular O2 delivery-to-utilization matching and accelerates exercise O2 uptake kinetics in chronic heart failure.

    PubMed

    Sperandio, Priscila A; Oliveira, Mayron F; Rodrigues, Miguel K; Berton, Danilo C; Treptow, Erika; Nery, Luiz E; Almeida, Dirceu R; Neder, J Alberto

    2012-12-15

    Nitric oxide (NO) can temporally and spatially match microvascular oxygen (O(2)) delivery (Qo(2mv)) to O(2) uptake (Vo(2)) in the skeletal muscle, a crucial adjustment-to-exercise tolerance that is impaired in chronic heart failure (CHF). To investigate the effects of NO bioavailability induced by sildenafil intake on muscle Qo(2mv)-to-O(2) utilization matching and Vo(2) kinetics, 10 males with CHF (ejection fraction = 27 ± 6%) undertook constant work-rate exercise (70-80% peak). Breath-by-breath Vo(2), fractional O(2)extraction in the vastus lateralis {∼deoxygenated hemoglobin + myoglobin ([deoxy-Hb + Mb]) by near-infrared spectroscopy}, and cardiac output (CO) were evaluated after sildenafil (50 mg) or placebo. Sildenafil increased exercise tolerance compared with placebo by ∼20%, an effect that was related to faster on- and off-exercise Vo(2) kinetics (P < 0.05). Active treatment, however, failed to accelerate CO dynamics (P > 0.05). On-exercise [deoxy-Hb + Mb] kinetics were slowed by sildenafil (∼25%), and a subsequent response "overshoot" (n = 8) was significantly lessened or even abolished. In contrast, [deoxy-Hb + Mb] recovery was faster with sildenafil (∼15%). Improvements in muscle oxygenation with sildenafil were related to faster on-exercise Vo(2) kinetics, blunted oscillations in ventilation (n = 9), and greater exercise capacity (P < 0.05). Sildenafil intake enhanced intramuscular Qo(2mv)-to-Vo(2) matching with beneficial effects on Vo(2) kinetics and exercise tolerance in CHF. The lack of effect on CO suggests that improvement in blood flow to and within skeletal muscles underlies these effects.

  20. Learning graph matching.

    PubMed

    Caetano, Tibério S; McAuley, Julian J; Cheng, Li; Le, Quoc V; Smola, Alex J

    2009-06-01

    As a fundamental problem in pattern recognition, graph matching has applications in a variety of fields, from computer vision to computational biology. In graph matching, patterns are modeled as graphs and pattern recognition amounts to finding a correspondence between the nodes of different graphs. Many formulations of this problem can be cast in general as a quadratic assignment problem, where a linear term in the objective function encodes node compatibility and a quadratic term encodes edge compatibility. The main research focus in this theme is about designing efficient algorithms for approximately solving the quadratic assignment problem, since it is NP-hard. In this paper we turn our attention to a different question: how to estimate compatibility functions such that the solution of the resulting graph matching problem best matches the expected solution that a human would manually provide. We present a method for learning graph matching: the training examples are pairs of graphs and the 'labels' are matches between them. Our experimental results reveal that learning can substantially improve the performance of standard graph matching algorithms. In particular, we find that simple linear assignment with such a learning scheme outperforms Graduated Assignment with bistochastic normalisation, a state-of-the-art quadratic assignment relaxation algorithm.

  1. Antithymocyte globulin improves the survival of patients with myelodysplastic syndrome undergoing HLA-matched unrelated donor and haplo-identical donor transplants

    PubMed Central

    Wang, Hong; Liu, Hong; Zhou, Jin-Yi; Zhang, Tong-Tong; Jin, Song; Zhang, Xiang; Chen, Su-Ning; Li, Wei-Yang; Xu, Yang; Miao, Miao; Wu, De-Pei

    2017-01-01

    Significant advances have been achieved in the outcomes of patients with myelodysplastic syndromes (MDS) after both HLA-matched sibling donor transplants (MSDT) and non-MSDT, the latter including HLA-matched unrelated donor (MUDT) and haplo-identical donor transplants (HIDT). In this retrospective study, we analyzed the data of 85 consecutive patients with MDS who received allogeneic HSCT between Dec 2007 and Apr 2014 in our center. These patients comprised 38 (44.7%) who received MSDT, 29 (34.1%) MUDT, and 18 (21.2%) HIDT. The median overall survival (OS) was 60.2 months, the probabilities of OS being 63%, 57%, and 48%, at the first, second, and fifth year, respectively. Median OS post-transplant (OSPT) was 57.2 months, the probabilities of OSPT being 58%, 55%, and 48% at the first, second, and fifth year, respectively. The survival of patients receiving non-MSDT was superior to that of MSDT, median OSPT being 84.0 months and 23.6 months, respectively (P = 0.042); the findings for OS were similar (P = 0.028). We also found that using ATG in conditioning regimens significantly improved survival after non-MSDT, with better OS and OSPT (P = 0.016 and P = 0.025). These data suggest that using ATG in conditioning regimens may improve the survival of MDS patients after non-MSDT. PMID:28262717

  2. The Balance Super Learner: A robust adaptation of the Super Learner to improve estimation of the average treatment effect in the treated based on propensity score matching.

    PubMed

    Pirracchio, Romain; Carone, Marco

    2016-01-01

    Consistency of the propensity score estimators rely on correct specification of the propensity score model. The propensity score is frequently estimated using a main effect logistic regression. It has recently been shown that the use of ensemble machine learning algorithms, such as the Super Learner, could improve covariate balance and reduce bias in a meaningful manner in the case of serious model misspecification for treatment assignment. However, the loss functions normally used by the Super Learner may not be appropriate for propensity score estimation since the goal in this problem is not to optimize propensity score prediction but rather to achieve the best possible balance in the covariate distribution between treatment groups. In a simulation study, we evaluated the benefit of a modification of the Super Learner by propensity score estimation geared toward achieving covariate balance between the treated and untreated after matching on the propensity score. Our simulation study included six different scenarios characterized by various degrees of deviation from the usual main term logistic model for the true propensity score and outcome as well as the presence (or not) of instrumental variables. Our results suggest that the use of this adapted Super Learner to estimate the propensity score can further improve the robustness of propensity score matching estimators.

  3. Invisible plasmonic meta-materials through impedance matching to vacuum

    NASA Astrophysics Data System (ADS)

    Lee, J. W.; Seo, M. A.; Sohn, J. Y.; Ahn, Y. H.; Kim, D. S.; Jeoung, S. C.; Lineau, Ch.; Park, Q.-Han

    2005-12-01

    We report on perfect transmission in two-dimensional plasmonic matamaterials in the terahertz frequency range, in which zeroth order transmittance becomes essentially unity near specific resonance frequencies. Perfect transmission may occur when the plasmonic metamaterials are perfectly impedance matched to vacuum, which is equivalent to designing an effective dielectric constant around ɛr = -2. When the effective dielectric constant of the metamaterial is tuned towards ɛr and the hole coverage is larger than 0.2, strong evanescent field builds up in the near field, making perfect transmission possible.

  4. Invisible plasmonic meta-materials through impedance matching to vacuum.

    PubMed

    Lee, J W; Seo, M A; Sohn, J Y; Ahn, Y H; Kim, D S; Jeoung, S C; Lienau, Ch; Park, Q-Han

    2005-12-26

    We report on perfect transmission in two-dimensional plasmonic matamaterials in the terahertz frequency range, in which zeroth order transmittance becomes essentially unity near specific resonance frequencies. Perfect transmission may occur when the plasmonic metamaterials are perfectly impedance matched to vacuum, which is equivalent to designing an effective dielectric constant around epsilonr = -2. When the effective dielectric constant of the metamaterial is tuned towards epsilonr and the hole coverage is larger than 0.2, strong evanescent field builds up in the near field, making perfect transmission possible.

  5. Color matching in facial prosthetics: A systematic review.

    PubMed

    Ranabhatt, Rani; Singh, Kamleshwar; Siddharth, Ramashanker; Tripathi, Shuchi; Arya, Deeksha

    2017-01-01

    Color matching to the surrounding skin is extremely important in patients wearing maxillofacial prostheses. It is of utmost importance to know the different techniques of color matching and coloring in maxillofacial prostheses. The purpose of this study is to review the literature data with regard to color matching in maxillofacial prosthetics. An electronic search of peer review restricted to English language dental literature was conducted to identify the relevant scientific article on color matching and coloring in maxillofacial prostheses. The publication year was up to December 2015 so that the search could include all the articles provided in that particular database. Two independent observers independently read the abstracts and later preselected full-text articles. A full-text review was carried out only for 15 articles. Out of the 15 articles, 7 were related to coloring using tinting, spraying, milling, and use of commercial cosmetics. Three studies were related to shade matching in maxillofacial prostheses. Two studies conducted the measurement of color in maxillofacial prostheses. Only one study had explained color and its relevance in maxillofacial prosthetics. Only one study was done for reproducing silicone shade guide matching Indian skin color. In addition, a single pilot study was done to measure facial skin and lip color in a human population sample stratified by race, gender, and age. Currently, there is no evidence discussing the best technique available for perfectly matching the color for the fabrication of maxillofacial prostheses. However, the latest instruments such as spectrophotometer and colorimeters are believed to have improved efficiency in matching the color.

  6. Screen-detected colorectal cancers are associated with an improved outcome compared with stage-matched interval cancers

    PubMed Central

    Gill, M D; Bramble, M G; Hull, M A; Mills, S J; Morris, E; Bradburn, D M; Bury, Y; Parker, C E; Lee, T J W; Rees, C J

    2014-01-01

    Background: Colorectal cancers (CRCs) detected through the NHS Bowel Cancer Screening Programme (BCSP) have been shown to have a more favourable outcome compared to non-screen-detected cancers. The aim was to identify whether this was solely due to the earlier stage shift of these cancers, or whether other factors were involved. Methods: A combination of a regional CRC registry (Northern Colorectal Cancer Audit Group) and the BCSP database were used to identify screen-detected and interval cancers (diagnosed after a negative faecal occult blood test, before the next screening round), diagnosed between April 2007 and March 2010, within the North East of England. For each Dukes' stage, patient demographics, tumour characteristics, and survival rates were compared between these two groups. Results: Overall, 322 screen-detected cancers were compared against 192 interval cancers. Screen-detected Dukes' C and D CRCs had a superior survival rate compared with interval cancers (P=0.014 and P=0.04, respectively). Cox proportional hazards regression showed that Dukes' stage, tumour location, and diagnostic group (HR 0.45, 95% CI 0.29–0.69, P<0.001 for screen-detected CRCs) were all found to have a significant impact on the survival of patients. Conclusions: The improved survival of screen-detected over interval cancers for stages C and D suggest that there may be a biological difference in the cancers in each group. Although lead-time bias may have a role, this may be related to a tumour's propensity to bleed and therefore may reflect detection through current screening tests. PMID:25247322

  7. Broadband quasi perfect absorption using chirped multi-layer porous materials

    NASA Astrophysics Data System (ADS)

    Jiménez, N.; Romero-García, V.; Cebrecos, A.; Picó, R.; Sánchez-Morcillo, V. J.; Garcia-Raffi, L. M.

    2016-12-01

    This work theoretically analyzes the sound absorption properties of a chirped multi-layer porous material including transmission, in particular showing the broadband unidirectional absorption properties of the system. Using the combination of the impedance matching condition and the balance between the leakage and the intrinsic losses, the system is designed to have broadband unidirectional and quasi perfect absorption. The transfer and scattering matrix formalism, together with numerical simulations based on the finite element method are used to demonstrate the results showing excellent agreement between them. The proposed system allows to construct broadband sound absorbers with improved absorption in the low frequency regime using less amount of material than the complete bulk porous layer.

  8. Improving recovery of ECG signal with deterministic guarantees using split signal for multiple supports of matching pursuit (SS-MSMP) algorithm.

    PubMed

    Tawfic, Israa Shaker; Kayhan, Sema Koc

    2017-02-01

    Compressed sensing (CS) is a new field used for signal acquisition and design of sensor that made a large drooping in the cost of acquiring sparse signals. In this paper, new algorithms are developed to improve the performance of the greedy algorithms. In this paper, a new greedy pursuit algorithm, SS-MSMP (Split Signal for Multiple Support of Matching Pursuit), is introduced and theoretical analyses are given. The SS-MSMP is suggested for sparse data acquisition, in order to reconstruct analog and efficient signals via a small set of general measurements. This paper proposes a new fast method which depends on a study of the behavior of the support indices through picking the best estimation of the corrosion between residual and measurement matrix. The term multiple supports originates from an algorithm; in each iteration, the best support indices are picked based on maximum quality created by discovering correlation for a particular length of support. We depend on this new algorithm upon our previous derivative of halting condition that we produce for Least Support Orthogonal Matching Pursuit (LS-OMP) for clear and noisy signal. For better reconstructed results, SS-MSMP algorithm provides the recovery of support set for long signals such as signals used in WBAN. Numerical experiments demonstrate that the new suggested algorithm performs well compared to existing algorithms in terms of many factors used for reconstruction performance. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Synergistic effect of KIR ligands missing and cytomegalovirus reactivation in improving outcomes of haematopoietic stem cell transplantation from HLA-matched sibling donor for treatment of myeloid malignancies.

    PubMed

    Cardozo, Daniela Maira; Marangon, Amanda Vansan; da Silva, Rodrigo Fernandes; Aranha, Francisco José Penteado; Visentainer, Jeane Eliete Laguila; Bonon, Sandra Helena Alves; Costa, Sandra Cecília Botelho; Miranda, Eliana Cristina Martins; de Souza, Carmino Antonio; Guimarães, Fernando

    2016-10-01

    The goal of this study was to evaluate the influence of KIR-HLA genotypes on the outcome of patients undergoing treatment for haematological malignancies by non-T-depleted lymphocyte haematopoietic stem cell transplantation (HSCT) from HLA-matched sibling donors. The prospective study was conducted at the Center of Hematology, University of Campinas, and 50 patients and their donors were followed up from 2008 to 2014. KIR and HLA class I genes were genotyped and patients grouped based on the presence of KIR ligands combined with KIR genotype of their respective donors. Patients with all KIR ligands present (n=13) had a significantly higher (p=0.04) incidence of acute graft-versus-host-disease (GVHD) than patients with one or more KIR ligands missing (n=37). The overall survival following transplantation of patients with myeloid malignancies (n=27) was significantly higher (p=0.035) in the group with one or more KIR ligands missing (n=18) than in the group with all ligands present (n=9). Presence of KIR2DS2 was associated with a worsening of HSCT outcome while reactivation of cytomegalovirus (CMV) infection improved the outcome of patients with one or more KIR ligands missing. Our results indicate that KIR-HLA interactions affect the outcome of the HLA-matched transplantation, particularly in patients with myeloid malignancies.

  10. Mechanism of resonant perfect optical absorber, design rules, and applications

    NASA Astrophysics Data System (ADS)

    Guan, Zhiqiang; Wang, Wenqiang; Xu, Hongxing

    2016-11-01

    The mechanism of resonant perfect optical absorber (POA) is revealed by coupled mode method. The POA structures here is an air/grating/film/air four region asymmetric structures. Different with common POA structures that require metal film at the bottom to block the transmission of light, the film in our structures serves as a total internal reflection layer which blocks the transmission of light. To demonstrate that, mode dispersion analyses are provided for each mode by the phase plots of the scattering coefficients on each interface. The sufficient and necessary conditions of perfect optical absorption are derived from the phase matching conditions. Three analytical formulae are given for prompt and accurate design rules when the incident wavelength is slightly larger than the periodicity. Several fabrication schemes are discussed. The features of ultrathin structures, widely tunable POA wavelength, and high Q factor make our structures promising for applications in coherent thermal emission, filtering, sensing and modulation.

  11. Perfect crystals grown from imperfect interfaces

    PubMed Central

    Falub, Claudiu V.; Meduňa, Mojmír; Chrastina, Daniel; Isa, Fabio; Marzegalli, Anna; Kreiliger, Thomas; Taboada, Alfonso G.; Isella, Giovanni; Miglio, Leo; Dommann, Alex; von Känel, Hans

    2013-01-01

    The fabrication of advanced devices increasingly requires materials with different properties to be combined in the form of monolithic heterostructures. In practice this means growing epitaxial semiconductor layers on substrates often greatly differing in lattice parameters and thermal expansion coefficients. With increasing layer thickness the relaxation of misfit and thermal strains may cause dislocations, substrate bowing and even layer cracking. Minimizing these drawbacks is therefore essential for heterostructures based on thick layers to be of any use for device fabrication. Here we prove by scanning X-ray nanodiffraction that mismatched Ge crystals epitaxially grown on deeply patterned Si substrates evolve into perfect structures away from the heavily dislocated interface. We show that relaxing thermal and misfit strains result just in lattice bending and tiny crystal tilts. We may thus expect a new concept in which continuous layers are replaced by quasi-continuous crystal arrays to lead to dramatically improved physical properties. PMID:23880632

  12. Perfect crystals grown from imperfect interfaces.

    PubMed

    Falub, Claudiu V; Meduňa, Mojmír; Chrastina, Daniel; Isa, Fabio; Marzegalli, Anna; Kreiliger, Thomas; Taboada, Alfonso G; Isella, Giovanni; Miglio, Leo; Dommann, Alex; von Känel, Hans

    2013-01-01

    The fabrication of advanced devices increasingly requires materials with different properties to be combined in the form of monolithic heterostructures. In practice this means growing epitaxial semiconductor layers on substrates often greatly differing in lattice parameters and thermal expansion coefficients. With increasing layer thickness the relaxation of misfit and thermal strains may cause dislocations, substrate bowing and even layer cracking. Minimizing these drawbacks is therefore essential for heterostructures based on thick layers to be of any use for device fabrication. Here we prove by scanning X-ray nanodiffraction that mismatched Ge crystals epitaxially grown on deeply patterned Si substrates evolve into perfect structures away from the heavily dislocated interface. We show that relaxing thermal and misfit strains result just in lattice bending and tiny crystal tilts. We may thus expect a new concept in which continuous layers are replaced by quasi-continuous crystal arrays to lead to dramatically improved physical properties.

  13. The Perfect Storm and the Privatization of Public Higher Education

    ERIC Educational Resources Information Center

    Ehrenberg, Ronald G.

    2006-01-01

    During the last quarter of a century, public higher education institutions have found themselves buffeted by a perfect storm. This storm has led to discussions about the privatization of those institutions, which has implications for their ability to improve, or at least maintain, their quality and their accessibility to students from all…

  14. The Perfect Storm and the Privatization of Public Higher Education

    ERIC Educational Resources Information Center

    Ehrenberg, Ronald G.

    2006-01-01

    During the last quarter of a century, public higher education institutions have found themselves buffeted by a perfect storm. This storm has led to discussions about the privatization of those institutions, which has implications for their ability to improve, or at least maintain, their quality and their accessibility to students from all…

  15. Matching isotopic distributions from metabolically labeled samples.

    PubMed

    McIlwain, Sean; Page, David; Huttlin, Edward L; Sussman, Michael R

    2008-07-01

    In recent years stable isotopic labeling has become a standard approach for quantitative proteomic analyses. Among the many available isotopic labeling strategies, metabolic labeling is attractive for the excellent internal control it provides. However, analysis of data from metabolic labeling experiments can be complicated because the spacing between labeled and unlabeled forms of each peptide depends on its sequence, and is thus variable from analyte to analyte. As a result, one generally needs to know the sequence of a peptide to identify its matching isotopic distributions in an automated fashion. In some experimental situations it would be necessary or desirable to match pairs of labeled and unlabeled peaks from peptides of unknown sequence. This article addresses this largely overlooked problem in the analysis of quantitative mass spectrometry data by presenting an algorithm that not only identifies isotopic distributions within a mass spectrum, but also annotates matches between natural abundance light isotopic distributions and their metabolically labeled counterparts. This algorithm is designed in two stages: first we annotate the isotopic peaks using a modified version of the IDM algorithm described last year; then we use a probabilistic classifier that is supplemented by dynamic programming to find the metabolically labeled matched isotopic pairs. Such a method is needed for high-throughput quantitative proteomic metabolomic experiments measured via mass spectrometry. The primary result of this article is that the dynamic programming approach performs well given perfect isotopic distribution annotations. Our algorithm achieves a true positive rate of 99% and a false positive rate of 1% using perfect isotopic distribution annotations. When the isotopic distributions are annotated given 'expert' selected peaks, the same algorithm gets a true positive rate of 77% and a false positive rate of 1%. Finally, when annotating using machine selected peaks, which

  16. Matching isotopic distributions from metabolically labeled samples

    PubMed Central

    McIlwain, Sean; Page, David; Huttlin, Edward L.; Sussman, Michael R.

    2008-01-01

    Motivation: In recent years stable isotopic labeling has become a standard approach for quantitative proteomic analyses. Among the many available isotopic labeling strategies, metabolic labeling is attractive for the excellent internal control it provides. However, analysis of data from metabolic labeling experiments can be complicated because the spacing between labeled and unlabeled forms of each peptide depends on its sequence, and is thus variable from analyte to analyte. As a result, one generally needs to know the sequence of a peptide to identify its matching isotopic distributions in an automated fashion. In some experimental situations it would be necessary or desirable to match pairs of labeled and unlabeled peaks from peptides of unknown sequence. This article addresses this largely overlooked problem in the analysis of quantitative mass spectrometry data by presenting an algorithm that not only identifies isotopic distributions within a mass spectrum, but also annotates matches between natural abundance light isotopic distributions and their metabolically labeled counterparts. This algorithm is designed in two stages: first we annotate the isotopic peaks using a modified version of the IDM algorithm described last year; then we use a probabilistic classifier that is supplemented by dynamic programming to find the metabolically labeled matched isotopic pairs. Such a method is needed for high-throughput quantitative proteomic metabolomic experiments measured via mass spectrometry. Results: The primary result of this article is that the dynamic programming approach performs well given perfect isotopic distribution annotations. Our algorithm achieves a true positive rate of 99% and a false positive rate of 1% using perfect isotopic distribution annotations. When the isotopic distributions are annotated given ‘expert’ selected peaks, the same algorithm gets a true positive rate of 77% and a false positive rate of 1%. Finally, when annotating using

  17. Feature-accelerated block matching

    NASA Astrophysics Data System (ADS)

    Tao, Bo; Orchard, Michael T.

    1998-01-01

    We study the relationship between local features and block matching in this paper. We show that the use of many features can greatly improve the block matching results by introducing several fast block matching algorithms. The first algorithm is pixel decimation-based. We show that pixels with larger gradient magnitude have larger motion compensation error. Therefore for pixel decimation-based fast block matching, it benefits to subsample the block by selecting pixels with the largest gradient magnitude. Such a gradient-assisted adaptive pixel selection strategy greatly outperforms two other subsampling procedures proposed in previous literature. Fast block matching can achieve the optimal performance obtained using full search. We present a family of such fast block matching algorithm using various local features, such as block mean and variance. Our algorithm reduces more than 80 percent computation, while achieving the same performance as the full search. This present a brand new approach toward fast block matching algorithm design.

  18. Relaxation matching algorithm for moving photogrammetry

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Liu, Ke; Miao, Yinxiao; Zhu, Jigui

    2015-02-01

    Moving photogrammetry is an application of close range photogrammetry in industrial measurement to realize threedimensional coordinate measurement within large-scale volume. This paper describes an approach of relaxation matching algorithm applicable to moving photogrammetry according to the characteristics of accurate matching result of different measuring images. This method uses neighborhood matching support to improve the matching rate after coarse matching based on epipolar geometry constraint and precise matching using three images. It reflects the overall matching effect of all points, that means when a point is matched correctly, the matching results of those points round it must be correct. So for one point considered, the matching results of points round it are calculated to judge whether its result is correct. Analysis indicates that relaxation matching can eliminate the mismatching effectively and acquire 100% rate of correct matching. It will play a very important role in moving photogrammetry to ensure the following implement of ray bundle adjustment.

  19. Nitinol stenting improves primary patency of the superficial femoral artery after percutaneous transluminal angioplasty in hemodialysis patients: a propensity-matched analysis.

    PubMed

    Kawamura, Yoshihiro; Ishii, Hideki; Aoyama, Toru; Tanaka, Miho; Takahashi, Hiroshi; Kumada, Yoshitaka; Toriyama, Takanobu; Murohara, Toyoaki

    2009-11-01

    Although percutaneous transluminal angioplasty (PTA) has become a common therapeutic standard for peripheral artery disease (PAD), high restenosis rates in the superficial femoral artery (SFA) remain a major problem. Nitinol stent implantation is reported to reduce restenosis in SFA after PTA in the general population; however, little is known about whether the nitinol stent improves primary patency after PTA in hemodialysis patients who are at higher risk of revascularization failure. The aim of this study was to clarify the effects of nitinol stent implantation for primary patency in SFA after PTA in hemodialysis patients with PAD. Eighty consecutive hemodialysis patients (167 SFA lesions) who underwent PTA with nitinol stents from January 2006 to January 2008 were compared with 64 hemodialysis patients (128 SFA lesions) who received stainless steel stents in the preceding 2 years. In the follow-up study to 2 years, incidence of restenosis, amputation, and all-cause mortality were analyzed. End points between the groups were examined with the Kaplan-Meier and log-rank methods. Prognostic values for end points were calculated by a Cox univariate analysis and Cox multivariable regression models. To statistically minimize the differences in each stent group, a propensity-matched analysis was also performed using the model including male gender, age, diabetes, hypertension, hyperlipidemia, smoking, incidence of ulcer/gangrene, and TransAtlantic Inter-Society Consensus (TASC) type C+D. The 2-year primary patency rate was 58% in the nitinol group vs 42% in the stainless steel group (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.39-0.84; P = .0045), despite a higher prevalence of TASC C+D lesion in the nitinol group (68% vs 49%, P = .0014). In 108 lesions matched after propensity score analysis, the primary patency for 2 years was 64% in the nitinol group vs 42% in the stainless steel group (HR, 0.39; 95% CI, 0.24-0.65; P = .0003). Cox multivariate models

  20. Perfect monochromatic acoustic anti-reflection: A first-principles study

    NASA Astrophysics Data System (ADS)

    Zhu, XingFeng; Wei, Qi; Cheng, Ying; Wu, DaJian; Liu, XiaoJun

    2017-03-01

    A first-principles method is introduced to design and achieve perfect monochromatic acoustic anti-reflection (AR) at any frequency. We established the relationship between the mass density and bulk modulus of the AR coating, which enabled the removal of any impedance mismatch. Perfect acoustic AR was realized by designing explicit conditions for the impedance matching. Theoretical results were numerically obtained using the finite element method. Importantly, perfect monochromatic acoustic AR was even realized for an ultra-thin AR layer at a deep subwavelength scale. We further approximated a multilayered AR coating with varying bulk moduli, which could provide perfect AR at any frequency. This ultra-thin multilayered AR structure may be beneficial for the minimization and integration of related acoustic devices.

  1. Computation of Thermally Perfect Compressible Flow Properties

    NASA Technical Reports Server (NTRS)

    Witte, David W.; Tatum, Kenneth E.; Williams, S. Blake

    1996-01-01

    A set of compressible flow relations for a thermally perfect, calorically imperfect gas are derived for a value of c(sub p) (specific heat at constant pressure) expressed as a polynomial function of temperature and developed into a computer program, referred to as the Thermally Perfect Gas (TPG) code. The code is available free from the NASA Langley Software Server at URL http://www.larc.nasa.gov/LSS. The code produces tables of compressible flow properties similar to those found in NACA Report 1135. Unlike the NACA Report 1135 tables which are valid only in the calorically perfect temperature regime the TPG code results are also valid in the thermally perfect, calorically imperfect temperature regime, giving the TPG code a considerably larger range of temperature application. Accuracy of the TPG code in the calorically perfect and in the thermally perfect, calorically imperfect temperature regimes are verified by comparisons with the methods of NACA Report 1135. The advantages of the TPG code compared to the thermally perfect, calorically imperfect method of NACA Report 1135 are its applicability to any type of gas (monatomic, diatomic, triatomic, or polyatomic) or any specified mixture of gases, ease-of-use, and tabulated results.

  2. Using social-emotional and character development to improve academic outcomes: a matched-pair, cluster-randomized controlled trial in low-income, urban schools.

    PubMed

    Bavarian, Niloofar; Lewis, Kendra M; Dubois, David L; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J; Day, Joseph; Ji, Peter; Flay, Brian R

    2013-11-01

    School-based social-emotional and character development (SECD) programs can influence not only SECD but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. The longitudinal study used a matched-pair, cluster-randomized controlled design. Student-reported disaffection with learning and academic grades, and teacher ratings of academic ability and motivation were assessed for a cohort followed from grades 3 to 8. Aggregate school records were used to assess standardized test performance (for entire school, cohort, and demographic subgroups) and absenteeism (entire school). Multilevel growth-curve analyses tested program effects. PA significantly improved growth in academic motivation and mitigated disaffection with learning. There was a positive impact of PA on absenteeism and marginally significant impact on math performance of all students. There were favorable program effects on reading for African American boys and cohort students transitioning between grades 7 and 8, and on math for girls and low-income students. A school-based SECD program was found to influence academic outcomes among students living in low-income, urban communities. Future research should examine mechanisms by which changes in SECD influence changes in academic outcomes. © 2013, American School Health Association.

  3. Using social-emotional and character development to improve academic outcomes: a matched-pair, cluster-randomized controlled trial in low-income, urban schools

    PubMed Central

    Lewis, Kendra M.; DuBois, David L.; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J.; Day, Joseph; Ji, Peter; Flay, Brian R.

    2013-01-01

    BACKGROUND School-based social-emotional and character development (SECD) programs can influence not only SECD, but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. METHODS The longitudinal study used a matched-pair, cluster-randomized controlled design. Student-reported disaffection with learning and academic grades, and teacher ratings of academic ability and motivation were assessed for a cohort followed from grades 3 to 8. Aggregate school records were used to assess standardized test performance (for entire school, cohort, and demographic subgroups) and absenteeism (entire school). Multilevel growth-curve analyses tested program effects. RESULTS PA significantly improved growth in academic motivation and mitigated disaffection with learning. There was a positive impact of PA on absenteeism and marginally significant impact on math performance of all students. There were favorable program effects on reading for African American boys and cohort students transitioning between grades 7 and 8, and on math for girls and low-income students. CONCLUSIONS A school-based SECD program was found to influence academic outcomes among students living in low-income, urban communities. Future research should examine mechanisms by which changes in SECD influence changes in academic outcomes. PMID:24138347

  4. Constraint-induced therapy versus dose-matched control intervention to improve motor ability, basic/extended daily functions, and quality of life in stroke.

    PubMed

    Lin, Keh-chung; Wu, Ching-yi; Liu, Jung-sen; Chen, Yueh-tsen; Hsu, Chen-jung

    2009-02-01

    Trials of constraint-induced movement therapy (CIT) to improve upper extremity function after stroke have usually not included an actively treated control group. This study compared a modified CIT intervention with a dose-matched control intervention that included restraint of the less affected hand and assessed for differences in motor and functional performance and health-related quality of life. This 2-group randomized controlled trial, using pretreatment and posttreatment measures, enrolled 32 patients within 6 to 40 months after onset of a first stroke (mean age, 55.7 years). They received either CIT (restraint of the less affected limb combined with intensive training of the affected limb for 2 hours daily 5 days per week for 3 weeks and restraint of the less affected hand for 5 hours outside of the rehabilitation training) or a conventional intervention with hand restraint for the same duration. Outcome measures were the Fugl-Meyer Assessment, Functional Independence Measure, Motor Activity Log, Nottingham Extended Activities of Daily Living Scale, and Stroke Impact Scale. Compared with the control group, the CIT group exhibited significantly better performance in motor function, level of functional independence, mobility of extended activities during daily life, and health-related quality of life after treatment. The robust effects of this form of CIT were demonstrated in various aspects of outcome, including motor function, basic and extended functional ability, and quality of life.

  5. Measurement of 3-D Vibrational Motion by Dynamic Photogrammetry Using Least-Square Image Matching for Sub-Pixel Targeting to Improve Accuracy

    PubMed Central

    Lee, Hyoseong; Rhee, Huinam; Oh, Jae Hong; Park, Jin Ho

    2016-01-01

    This paper deals with an improved methodology to measure three-dimensional dynamic displacements of a structure by digital close-range photogrammetry. A series of stereo images of a vibrating structure installed with targets are taken at specified intervals by using two daily-use cameras. A new methodology is proposed to accurately trace the spatial displacement of each target in three-dimensional space. This method combines the correlation and the least-square image matching so that the sub-pixel targeting can be obtained to increase the measurement accuracy. Collinearity and space resection theory are used to determine the interior and exterior orientation parameters. To verify the proposed method, experiments have been performed to measure displacements of a cantilevered beam excited by an electrodynamic shaker, which is vibrating in a complex configuration with mixed bending and torsional motions simultaneously with multiple frequencies. The results by the present method showed good agreement with the measurement by two laser displacement sensors. The proposed methodology only requires inexpensive daily-use cameras, and can remotely detect the dynamic displacement of a structure vibrating in a complex three-dimensional defection shape up to sub-pixel accuracy. It has abundant potential applications to various fields, e.g., remote vibration monitoring of an inaccessible or dangerous facility. PMID:26978366

  6. Measurement of 3-D Vibrational Motion by Dynamic Photogrammetry Using Least-Square Image Matching for Sub-Pixel Targeting to Improve Accuracy.

    PubMed

    Lee, Hyoseong; Rhee, Huinam; Oh, Jae Hong; Park, Jin Ho

    2016-03-11

    This paper deals with an improved methodology to measure three-dimensional dynamic displacements of a structure by digital close-range photogrammetry. A series of stereo images of a vibrating structure installed with targets are taken at specified intervals by using two daily-use cameras. A new methodology is proposed to accurately trace the spatial displacement of each target in three-dimensional space. This method combines the correlation and the least-square image matching so that the sub-pixel targeting can be obtained to increase the measurement accuracy. Collinearity and space resection theory are used to determine the interior and exterior orientation parameters. To verify the proposed method, experiments have been performed to measure displacements of a cantilevered beam excited by an electrodynamic shaker, which is vibrating in a complex configuration with mixed bending and torsional motions simultaneously with multiple frequencies. The results by the present method showed good agreement with the measurement by two laser displacement sensors. The proposed methodology only requires inexpensive daily-use cameras, and can remotely detect the dynamic displacement of a structure vibrating in a complex three-dimensional defection shape up to sub-pixel accuracy. It has abundant potential applications to various fields, e.g., remote vibration monitoring of an inaccessible or dangerous facility.

  7. Is matching innate?

    PubMed

    Gallistel, C R; King, Adam Philip; Gottlieb, Daniel; Balci, Fuat; Papachristos, Efstathios B; Szalecki, Matthew; Carbone, Kimberly S

    2007-03-01

    Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling. Matching was observed from the outset; it did not improve with training. When the numbers of pellets received were proportional to time invested, investment was unstable, swinging abruptly from sustained, almost complete investment in one hopper, to sustained, almost complete investment in the other-in the absence of appropriate local fluctuations in returns (pellets obtained per time invested). The abruptness of the swings strongly constrains possible models. We suggest that matching reflects an innate (unconditioned) program that matches the ratio of expected visit durations to the ratio between the current estimates of expected incomes. A model that processes the income stream looking for changes in the income and generates discontinuous income estimates when a change is detected is shown to account for salient features of the data.

  8. Factorized Graph Matching.

    PubMed

    Zhou, Feng; de la Torre, Fernando

    2015-11-19

    Graph matching (GM) is a fundamental problem in computer science, and it plays a central role to solve correspondence problems in computer vision. GM problems that incorporate pairwise constraints can be formulated as a quadratic assignment problem (QAP). Although widely used, solving the correspondence problem through GM has two main limitations: (1) the QAP is NP-hard and difficult to approximate; (2) GM algorithms do not incorporate geometric constraints between nodes that are natural in computer vision problems. To address aforementioned problems, this paper proposes factorized graph matching (FGM). FGM factorizes the large pairwise affinity matrix into smaller matrices that encode the local structure of each graph and the pairwise affinity between edges. Four are the benefits that follow from this factorization: (1) There is no need to compute the costly (in space and time) pairwise affinity matrix; (2) The factorization allows the use of a path-following optimization algorithm, that leads to improved optimization strategies and matching performance; (3) Given the factorization, it becomes straight-forward to incorporate geometric transformations (rigid and non-rigid) to the GM problem. (4) Using a matrix formulation for the GM problem and the factorization, it is easy to reveal commonalities and differences between different GM methods. The factorization also provides a clean connection with other matching algorithms such as iterative closest point; Experimental results on synthetic and real databases illustrate how FGM outperforms state-of-the-art algorithms for GM. The code is available at http://humansensing.cs.cmu.edu/fgm.

  9. Conditions for creating perfectly secure systems

    NASA Astrophysics Data System (ADS)

    Styugin, M.

    2016-11-01

    The present paper reviews a method for establishing secure information systems by complicating the possibility to research them for potential adversaries. A formalized model of a researcher and a definition of a research secure system are presented. A theorem for conditions required for creating a system perfectly secured from research. The Shannon's theorem of absolute security of perfect secrecy ciphers in cryptography is an instance of the theorem presented in the paper.

  10. Matching Supernovae to Galaxies

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-12-01

    developed a new automated algorithm for matching supernovae to their host galaxies. Their work builds on currently existing algorithms and makes use of information about the nearby galaxies, accounts for the uncertainty of the match, and even includes a machine learning component to improve the matching accuracy.Gupta and collaborators test their matching algorithm on catalogs of galaxies and simulated supernova events to quantify how well the algorithm is able to accurately recover the true hosts.Successful MatchingThe matching algorithms accuracy (purity) as a function of the true supernova-host separation, the supernova redshift, the true hosts brightness, and the true hosts size. [Gupta et al. 2016]The authors find that when the basic algorithm is run on catalog data, it matches supernovae to their hosts with 91% accuracy. Including the machine learning component, which is run after the initial matching algorithm, improves the accuracy of the matching to 97%.The encouraging results of this work which was intended as a proof of concept suggest that methods similar to this could prove very practical for tackling future survey data. And the method explored here has use beyond matching just supernovae to their host galaxies: it could also be applied to other extragalactic transients, such as gamma-ray bursts, tidal disruption events, or electromagnetic counterparts to gravitational-wave detections.CitationRavi R. Gupta et al 2016 AJ 152 154. doi:10.3847/0004-6256/152/6/154

  11. Random perfect lattices and the sphere packing problem

    NASA Astrophysics Data System (ADS)

    Andreanov, A.; Scardicchio, A.

    2012-10-01

    Motivated by the search for best lattice sphere packings in Euclidean spaces of large dimensions we study randomly generated perfect lattices in moderately large dimensions (up to d=19 included). Perfect lattices are relevant in the solution of the problem of lattice sphere packing, because the best lattice packing is a perfect lattice and because they can be generated easily. Their number, however, grows superexponentially with the dimension, so to get an idea of their properties we propose to study a randomized version of the generating algorithm and to define a random ensemble with an effective temperature in a way reminiscent of a Monte Carlo simulation. We therefore study the distribution of packing fractions and kissing numbers of these ensembles and show how as the temperature is decreased the best known packers are easily recovered. We find that, even at infinite temperature, the typical perfect lattices are considerably denser than known families (like Ad and Dd), and we propose two hypotheses between which we cannot distinguish in this paper: one in which they improve the Minkowsky bound φ˜2-(0.84±0.06)d, and a competitor in which their packing fraction decreases superexponentially, namely, φ˜d-ad but with a very small coefficient a=0.06±0.04. We also find properties of the random walk which are suggestive of a glassy system already for moderately small dimensions. We also analyze local structure of network of perfect lattices conjecturing that this is a scale-free network in all dimensions with constant scaling exponent 2.6±0.1.

  12. Random perfect lattices and the sphere packing problem.

    PubMed

    Andreanov, A; Scardicchio, A

    2012-10-01

    Motivated by the search for best lattice sphere packings in Euclidean spaces of large dimensions we study randomly generated perfect lattices in moderately large dimensions (up to d=19 included). Perfect lattices are relevant in the solution of the problem of lattice sphere packing, because the best lattice packing is a perfect lattice and because they can be generated easily. Their number, however, grows superexponentially with the dimension, so to get an idea of their properties we propose to study a randomized version of the generating algorithm and to define a random ensemble with an effective temperature in a way reminiscent of a Monte Carlo simulation. We therefore study the distribution of packing fractions and kissing numbers of these ensembles and show how as the temperature is decreased the best known packers are easily recovered. We find that, even at infinite temperature, the typical perfect lattices are considerably denser than known families (like A(d) and D(d)), and we propose two hypotheses between which we cannot distinguish in this paper: one in which they improve the Minkowsky bound φ~2(-(0.84±0.06)d), and a competitor in which their packing fraction decreases superexponentially, namely, φ~d(-ad) but with a very small coefficient a=0.06±0.04. We also find properties of the random walk which are suggestive of a glassy system already for moderately small dimensions. We also analyze local structure of network of perfect lattices conjecturing that this is a scale-free network in all dimensions with constant scaling exponent 2.6±0.1.

  13. Pursuing the perfect patient experience.

    PubMed

    Kaplan, Gary S

    2013-01-01

    Adapting the principles and tools of the Toyota Production System to healthcare in the form of the Virginia Mason Production System has enabled Virginia Mason Medical Center to transform itself as an organization. Virginia Mason has worked persistently for more than a decade to apply Toyota methods to eliminate waste, improve safety and quality, and provide the community it serves with the highest-quality healthcare at the lowest cost. We have made great progress in this pursuit.

  14. SNV-PPILP: refined SNV calling for tumor data using perfect phylogenies and ILP.

    PubMed

    van Rens, Karen E; Mäkinen, Veli; Tomescu, Alexandru I

    2015-04-01

    Recent studies sequenced tumor samples from the same progenitor at different development stages and showed that by taking into account the phylogeny of this development, single-nucleotide variant (SNV) calling can be improved. Accurate SNV calls can better reveal early-stage tumors, identify mechanisms of cancer progression or help in drug targeting. We present SNV-PPILP, a fast and easy to use tool for refining GATK's Unified Genotyper SNV calls, for multiple samples assumed to form a phylogeny. We tested SNV-PPILP on simulated data, with a varying number of samples, SNVs, read coverage and violations of the perfect phylogeny assumption. We always match or improve the accuracy of GATK, with a significant improvement on low read coverage. SNV-PPILP, available at cs.helsinki.fi/gsa/snv-ppilp/, is written in Python and requires the free ILP solver lp_solve. Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Persistent Perfect Entanglement in Atomic Systems

    NASA Astrophysics Data System (ADS)

    Ali Can, Muhammet

    2004-03-01

    It has been shown recently [1] that a pure entangled state of two-level atoms can be obtained in an optical resonator through the exchange by cavity photons. Unfortunately, the lifetime of such an entangled state, caused by the radiative decay time for the dipole transitions is very short. The situation can be improved through the use of three-level atoms with lambda-type transition [2]. In this case, the cavity field pumps transition between the lowest (ground) and highest (excited) states. Then, the decay of the excited state can populate the intermediate state. This is just the Raman-type process with emission of Stokes photon in atomic system. Because of the selection rules by the parity conservation, the dipole decay from the intermediate state to the ground state is forbidden. If the Stokes photons created by the transitions from the excited state to the ground state are discarded (through the use of cavity leakage of absorption), the final state of atomic system is stabile or at least durable. In the case of 2n three-level atoms, this can lead to the N-qubit perfect entangled state, where N=2j+1 and j is an odd ``spin'' corresponding to the SU(2) algebra in the Hilbert space H=(C2)^ otimes N In fact, these are the SU(2) phase states of odd ``spin'' have been discussed in [3] in the context of two-level atoms. The possibility to create and observe these states with present experimental technique is discussed. [1] A. Beige, S. Bose, D. Braun, S.F. Huelga, P.L. Knight, M.B. Plenio, and V. Verdal. J. Mod. Optics 47, 2583 (2000). [2] M.A. Can, A.A. Klyachko, and A.S. Shumovsky. Appl. Phys. Lett. 81, 5072 (2002). [3] M.A. Can, A.A. Klyachko, and A.S. Shumovsky. Phys. Rev. A 66, 022111 (2002).

  16. Relativistic perfect fluids in local thermal equilibrium

    NASA Astrophysics Data System (ADS)

    Coll, Bartolomé; Ferrando, Joan Josep; Sáez, Juan Antonio

    2017-05-01

    Every evolution of a fluid is uniquely described by an energy tensor. But the converse is not true: an energy tensor may describe the evolution of different fluids. The problem of determining them is called here the inverse problem. This problem may admit unphysical or non-deterministic solutions. This paper is devoted to solve the inverse problem for perfect energy tensors in the class of perfect fluids evolving in local thermal equilibrium (l.t.e.). The starting point is a previous result (Coll and Ferrando in J Math Phys 30:2918-2922, 1989) showing that thermodynamic fluids evolving in l.t.e. admit a purely hydrodynamic characterization. This characterization allows solving this inverse problem in a very compact form. The paradigmatic case of perfect energy tensors representing the evolution of ideal gases is studied in detail and some applications and examples are outlined.

  17. Overlapped optics induced perfect coherent effects

    NASA Astrophysics Data System (ADS)

    Li, Jian Jie; Zang, Xiao Fei; Mao, Jun Fa; Tang, Min; Zhu, Yi Ming; Zhuang, Song Lin

    2013-12-01

    For traditional coherent effects, two separated identical point sources can be interfered with each other only when the optical path difference is integer number of wavelengths, leading to alternate dark and bright fringes for different optical path difference. For hundreds of years, such a perfect coherent condition seems insurmountable. However, in this paper, based on transformation optics, two separated in-phase identical point sources can induce perfect interference with each other without satisfying the traditional coherent condition. This shifting illusion media is realized by inductor-capacitor transmission line network. Theoretical analysis, numerical simulations and experimental results are performed to confirm such a kind of perfect coherent effect and it is found that the total radiation power of multiple elements system can be greatly enhanced. Our investigation may be applicable to National Ignition Facility (NIF), Inertial Confined Fusion (ICF) of China, LED lighting technology, terahertz communication, and so on.

  18. Using Social-Emotional and Character Development to Improve Academic Outcomes: A Matched-Pair, Cluster-Randomized Controlled Trial in Low-Income, Urban Schools

    ERIC Educational Resources Information Center

    Bavarian, Niloofar; Lewis, Kendra M.; DuBois, David L.; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J.; Day, Joseph; Ji, Peter; Flay, Brian R.

    2013-01-01

    Background: School-based social-emotional and character development (SECD) programs can influence not only SECD but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. Methods: The longitudinal study used a matched-pair, cluster-randomized…

  19. A Modified Protocol with Improved Detection Rate for Mis-Matched Donor HLA from Low Quantities of DNA in Urine Samples from Kidney Graft Recipients.

    PubMed

    Kwok, Janette; Choi, Leo C W; Ho, Jenny C Y; Chan, Gavin S W; Mok, Maggie M Y; Lam, Man-Fei; Chak, Wai-Leung; Cheuk, Au; Chau, Ka-Foon; Tong, Matthew; Chan, Kwok-Wah; Chan, Tak-Mao

    2016-01-01

    Urine from kidney transplant recipient has proven to be a viable source for donor DNA. However, an optimized protocol would be required to determine mis-matched donor HLA specificities in view of the scarcity of DNA obtained in some cases. In this study, fresh early morning urine specimens were obtained from 155 kidney transplant recipients with known donor HLA phenotype. DNA was extracted and typing of HLA-A, B and DRB1 loci by polymerase chain reaction-specific sequence primers was performed using tailor-made condition according to the concentration of extracted DNA. HLA typing of DNA extracted from urine revealed both recipient and donor HLA phenotypes, allowing the deduction of the unknown donor HLA and hence the degree of HLA mis-match. By adopting the modified procedures, mis-matched donor HLA phenotypes were successfully deduced in all of 35 tested urine samples at DNA quantities spanning the range of 620-24,000 ng. This urine-based method offers a promising and reliable non-invasive means for the identification of mis-matched donor HLA antigens in kidney transplant recipients with unknown donor HLA phenotype or otherwise inadequate donor information.

  20. Using Social-Emotional and Character Development to Improve Academic Outcomes: A Matched-Pair, Cluster-Randomized Controlled Trial in Low-Income, Urban Schools

    ERIC Educational Resources Information Center

    Bavarian, Niloofar; Lewis, Kendra M.; DuBois, David L.; Acock, Alan; Vuchinich, Samuel; Silverthorn, Naida; Snyder, Frank J.; Day, Joseph; Ji, Peter; Flay, Brian R.

    2013-01-01

    Background: School-based social-emotional and character development (SECD) programs can influence not only SECD but also academic-related outcomes. This study evaluated the impact of one SECD program, Positive Action (PA), on educational outcomes among low-income, urban youth. Methods: The longitudinal study used a matched-pair, cluster-randomized…

  1. A Modified Protocol with Improved Detection Rate for Mis-Matched Donor HLA from Low Quantities of DNA in Urine Samples from Kidney Graft Recipients

    PubMed Central

    Kwok, Janette; Choi, Leo C. W.; Ho, Jenny C. Y.; Chan, Gavin S. W.; Mok, Maggie M. Y.; Lam, Man-Fei; Chak, Wai-Leung; Cheuk, Au; Chau, Ka-Foon; Tong, Matthew; Chan, Kwok-Wah; Chan, Tak-Mao

    2016-01-01

    Background Urine from kidney transplant recipient has proven to be a viable source for donor DNA. However, an optimized protocol would be required to determine mis-matched donor HLA specificities in view of the scarcity of DNA obtained in some cases. Methods In this study, fresh early morning urine specimens were obtained from 155 kidney transplant recipients with known donor HLA phenotype. DNA was extracted and typing of HLA-A, B and DRB1 loci by polymerase chain reaction-specific sequence primers was performed using tailor-made condition according to the concentration of extracted DNA. Results HLA typing of DNA extracted from urine revealed both recipient and donor HLA phenotypes, allowing the deduction of the unknown donor HLA and hence the degree of HLA mis-match. By adopting the modified procedures, mis-matched donor HLA phenotypes were successfully deduced in all of 35 tested urine samples at DNA quantities spanning the range of 620–24,000 ng. Conclusions This urine-based method offers a promising and reliable non-invasive means for the identification of mis-matched donor HLA antigens in kidney transplant recipients with unknown donor HLA phenotype or otherwise inadequate donor information. PMID:27861530

  2. [THE RIGHT TO A CHROMOSOMICALLY PERFECT CHILD].

    PubMed

    Vago, Philippe

    2015-07-01

    After defining the terms "perfect," "chromosomically" and "right" we discuss on the scope and terms of the right to a chromosomically perfect child. This right is it addressed to a target population or to the general population? What are the exams available and the means of diagnosis or screening to be implemented? The practice of genetic testing being highly controlled, some rules are then discussed. All over the paper, a reflection is proposed on what is allowed versus what is possible with reference to ethics.

  3. Selective coherent perfect absorption in metamaterials

    SciTech Connect

    Nie, Guangyu; Shi, Quanchao; Zhu, Zheng; Shi, Jinhui

    2014-11-17

    We show multi-band coherent perfect absorption (CPA) in simple bilayered asymmetrically split ring metamaterials. The selectivity of absorption can be accomplished by separately excited electric and magnetic modes in a standing wave formed by two coherent counterpropagating beams. In particular, each CPA can be completely switched on/off by the phase of a second coherent wave. We propose a practical scheme for realizing multi-band coherent perfect absorption of 100% that is allowed to work from microwave to optical frequency.

  4. Near-perfect diffraction grating rhomb

    DOEpatents

    Wantuck, Paul J.

    1990-01-01

    A near-perfect grating rhomb enables an output beam to be diffracted to an angle offset from the input beam. The correcting grating is tipped relative to the dispersing grating to provide the offset angle. The correcting grating is further provided with a groove spacing which differs from the dispersing grating groove space by an amount effective to substantially remove angular dispersion in the output beam. A near-perfect grating rhomb has the capability for selective placement in a FEL to suppress sideband instabilities arising from the FEL.

  5. Electromagnetic Detection of a Perfect Invisibility Cloak

    SciTech Connect

    Zhang Baile; Wu, Bae-Ian

    2009-12-11

    A perfect invisibility cloak is commonly believed to be undetectable from electromagnetic (EM) detection because it is equivalent to a curved but empty EM space created from coordinate transformation. Based on the intrinsic asymmetry of coordinate transformation applied to motions of photons and charges, we propose a method to detect this curved EM space by shooting a fast-moving charged particle through it. A broadband radiation generated in this process makes a cloak visible. Our method is the only known EM mechanism so far to detect an ideal perfect cloak (curved EM space) within its working band.

  6. Generation of perfect vectorial vortex beams.

    PubMed

    Li, Peng; Zhang, Yi; Liu, Sheng; Ma, Chaojie; Han, Lei; Cheng, Huachao; Zhao, Jianlin

    2016-05-15

    We propose the concept of perfect vectorial vortex beams (VVBs), which not merely have intensity profile independent of the polarization order and the topological charge of spiral phase, but also have stable intensity profile and state of polarization (SoP) upon propagation. Utilizing a Sagnac interferometer, we approximately generate perfect VVBs with locally linear and elliptical polarizations, and demonstrate that such beams can keep their intensity profile and SoP at a certain propagation distance. These proposed VVBs can be expanded to encode information and quantum cryptography, as well as to enrich the conversion of spin and orbital angular momenta.

  7. Energy-matched moderate and high intensity exercise training improves nonalcoholic fatty liver disease risk independent of changes in body mass or abdominal adiposity - a randomized trial.

    PubMed

    Winn, Nathan C; Ying, Liu; Rector, R Scott; Parks, Elizabeth J; Ibdah, Jamal A; Kanaley, Jill A

    2017-09-20

    Exercise training is commonly prescribed for individuals diagnosed with nonalcoholic fatty liver disease (NAFLD); however, consensus regarding the volume and intensity of exercise for optimal benefits is lacking. Thus, we determined whether high intensity interval exercise training (HIIT) produced greater reductions in intrahepatic lipid (IHL) content and NAFLD risk factors compared with energy-matched moderate intensity continuous exercise training (MICT) in obese adults with liver steatosis. Eighteen obese adults were randomized to either 4 weeks of HIIT (4 min 80% VO2peak/3 min, 50% VO2peak) or MICT (55% VO2peak, ~60 min), matched for energy expenditure (~400 kcal/session) and compared to five non-exercising age-matched control subjects. IHL was measured by (1)H-MRS and frequent blood samples were analyzed for glucose, insulin, c-peptide, and NEFA levels during a liquid meal test (180 min) to characterize metabolic phenotype. Baseline body weight, visceral abdominal adiposity, and fasting insulin concentrations were greater in the MICT vs HIIT group (P<0.05), while IHL was tightly matched between MICT and HIIT subjects (P>0.05), albeit higher than control subjects (P<0.01). Visceral abdominal adiposity, body mass, liver aminotransferases (ALT, AST), and hepatic apoptotic/inflammatory markers (cytokeratin 18 and fetuin a) were not reduced with either exercise training intervention (P>0.05). Both HIIT and MICT lowered IHL (HIIT, -37.0±12.4%; MICT, -20.1±6.6%, P<0.05); however, the reduction in IHL was not statistically different between exercise intensities (P=0.25). Furthermore, exercise training decreased postprandial insulin, c-peptide, and lipid peroxidation levels (iAUC, P<0.05). Collectively, these findings indicate that energy-matched high intensity and moderate intensity exercise are effective at decreasing IHL and NAFLD risk that is not contingent upon reductions in abdominal adiposity or body mass. Copyright © 2017. Published by Elsevier Inc.

  8. Hybrid Schema Matching for Deep Web

    NASA Astrophysics Data System (ADS)

    Chen, Kerui; Zuo, Wanli; He, Fengling; Chen, Yongheng

    Schema matching is the process of identifying semantic mappings, or correspondences, between two or more schemas. Schema matching is a first step and critical part of data integration. For schema matching of deep web, most researches only interested in query interface, while rarely pay attention to abundant schema information contained in query result pages. This paper proposed a mixed schema matching technique, which combines attributes that appeared in query structures and query results of different data sources, and mines the matched schemas inside. Experimental results prove the effectiveness of this method for improving the accuracy of schema matching.

  9. Broadband perfect absorber based on one ultrathin layer of refractory metal.

    PubMed

    Deng, Huixu; Li, Zhigang; Stan, Liliana; Rosenmann, Daniel; Czaplewski, David; Gao, Jie; Yang, Xiaodong

    2015-06-01

    Broadband perfect absorber based on one ultrathin layer of the refractory metal chromium without structure patterning is proposed and demonstrated. The ideal permittivity of the metal layer for achieving broadband perfect absorption is derived based on the impedance transformation method. Since the permittivity of the refractory metal chromium matches this ideal permittivity well in the visible and near-infrared range, a silica-chromium-silica three-layer absorber is fabricated to demonstrate the broadband perfect absorption. The experimental results under normal incidence show that the absorption is above 90% over the wavelength range of 0.4-1.4 μm, and the measurements under angled incidence within 400-800 nm prove that the absorber is angle-insensitive and polarization-independent.

  10. Tunable perfect absorber supported by accumulation electron gas at ITO-dielectric heterointerface

    NASA Astrophysics Data System (ADS)

    Li, Liang; Zhao, Hua; Zhang, Jingwen

    2017-10-01

    Absorption of an photonic configuration with 2D accumulation electron gas is theoretically investigated in the first optical window of biological tissue. The configuration consists of a Bragg mirror, an ITO-dielectric heterostructure and a metal film. Our results show that the configuration can realize perfect absorption (reaches 99.98%) of specific wavelength light at matched electron density of the accumulation electron gas. Moreover, the influences of different parameters on the perfect absorption are investigated, which allows us accurately tune the absorption spectrum of the configuration. In addition, manufacture discrepancies of film thicknesses are simulated through introducing random thickness errors in the configuration. It is found that the discrepancies of film thicknesses dramatically affect the absorption spectrum of the configuration. Fortunately, this manufacture impact can be perfectly remedied by changing the electron density of the accumulation electron gas and the incident angle of light.

  11. Broadband perfect absorber based on one ultrathin layer of refractory metal

    SciTech Connect

    Deng, Huixu; Li, Zhigang; Stan, Liliana; Rosenmann, Daniel; Czaplewski, David; Gao, Jie; Yang, Xiaodong

    2015-06-01

    Broadband perfect absorber based on one ultrathin layer of the refractory metal chromium without structure pat- terning is proposed and demonstrated. The ideal permittivity of the metal layer for achieving broadband perfect absorption is derived based on the impedance transformation method. Since the permittivity of the refractory metal chromium matches this ideal permittivity well in the visible and near-infrared range, a silica-chromium-silica three-layer absorber is fabricated to demonstrate the broadband perfect absorption. The experimental results under normal incidence show that the absorption is above 90% over the wavelength range of 0.4–1.4 μm, and the measurements under angled incidence within 400–800 nm prove that the absorber is angle-insensitive and polarization- independent.

  12. The Present Perfect in World Englishes

    ERIC Educational Resources Information Center

    Yao, Xinyue; Collins, Peter

    2012-01-01

    This paper reports on a comprehensive corpus-based study of regional and stylistic variation in the distribution of the English present perfect. The data represents ten English varieties of both the Inner Circle and Outer Circle, covering four major text types: conversation, news reportage, academic and fictional writing. The results are discussed…

  13. Perfect Phylogeny Problems with Missing Values.

    PubMed

    Kirkpatrick, Bonnie; Stevens, Kristian

    2014-01-01

    The perfect phylogeny problem is of central importance to both evolutionary biology and population genetics. Missing values are a common occurrence in both sequence and genotype data, but they make the problem of finding a perfect phylogeny NPhard even for binary characters. We introduce new and efficient perfect phylogeny algorithms for broad classes of binary and multistate data with missing values. Specifically, we address binary missing data consistent with the rich data hypothesis (RDH) introduced by Halperin and Karp and give an efficient algorithm for enumerating phylogenies. This algorithm is useful for computing the probability of data with missing values under the coalescent model. In addition, we use the partition intersection (PI) graph and chordal graph theory to generalize the RDH to multi-state characters with missing values. For a bounded number of states, we provide a fixed parameter tractable algorithm for the perfect phylogeny problem with missing data. Utilizing the PI graph, we are able to show that under multiple biologically motivated models for character data, our generalized RDH holds with high probability, and we evaluate our results with extensive empirical analysis.

  14. The Ambiguity of the English Present Perfect.

    ERIC Educational Resources Information Center

    Michaelis, Laura A.

    1994-01-01

    Examines grammatical and discourse-pragmatic reflexes of the existential and resultative readings of the English present perfect and presents negative and positive arguments regarding its ambiguity. It is suggested that the resultative verb represents a formal idiom and that mastery of aspectual grammar entails knowledge of form-meaning pairings.…

  15. Perfect Day: A Meditation about Teaching

    ERIC Educational Resources Information Center

    Valadez, Gilbert

    2004-01-01

    When asked by a student in a seminar recently if he could remember a perfect day teaching elementary school, the author writes memories of one he distinctly remembers because he gained new insight into teaching on that particular day. After returning to work following the devastating loss of a younger 19 year-old brother in a car crash, he resumed…

  16. Perfect Day: A Meditation about Teaching

    ERIC Educational Resources Information Center

    Valadez, Gilbert

    2004-01-01

    When asked by a student in a seminar recently if he could remember a perfect day teaching elementary school, the author writes memories of one he distinctly remembers because he gained new insight into teaching on that particular day. After returning to work following the devastating loss of a younger 19 year-old brother in a car crash, he resumed…

  17. Maple Explorations, Perfect Numbers, and Mersenne Primes

    ERIC Educational Resources Information Center

    Ghusayni, B.

    2005-01-01

    Some examples from different areas of mathematics are explored to give a working knowledge of the computer algebra system Maple. Perfect numbers and Mersenne primes, which have fascinated people for a very long time and continue to do so, are studied using Maple and some questions are posed that still await answers.

  18. The Ambiguity of the English Present Perfect.

    ERIC Educational Resources Information Center

    Michaelis, Laura A.

    1994-01-01

    Examines grammatical and discourse-pragmatic reflexes of the existential and resultative readings of the English present perfect and presents negative and positive arguments regarding its ambiguity. It is suggested that the resultative verb represents a formal idiom and that mastery of aspectual grammar entails knowledge of form-meaning pairings.…

  19. Mechanical Energy Changes in Perfectly Inelastic Collisions

    ERIC Educational Resources Information Center

    Mungan, Carl E.

    2013-01-01

    Suppose a block of mass "m"[subscript 1] traveling at speed "v"[subscript 1] makes a one-dimensional perfectly inelastic collision with another block of mass "m"[subscript 2]. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision? (Contains 1 figure.)

  20. The Present Perfect in World Englishes

    ERIC Educational Resources Information Center

    Yao, Xinyue; Collins, Peter

    2012-01-01

    This paper reports on a comprehensive corpus-based study of regional and stylistic variation in the distribution of the English present perfect. The data represents ten English varieties of both the Inner Circle and Outer Circle, covering four major text types: conversation, news reportage, academic and fictional writing. The results are discussed…

  1. Designing a perfect cornea: computational aspects

    NASA Astrophysics Data System (ADS)

    Rubinstein, Jacob; Wolansky, Gershon

    2002-12-01

    We analyze an algorithm for the design of a perfect cornea that exactly focuses a preselected object or a preselected wave front on the retina. The algorithm can be used, for example, in refractive surgery. We consider the sensitivity of the algorithm to various errors, including errors in the measurements of the aberrations, the original corneal topography and the ablation process.

  2. Maple Explorations, Perfect Numbers, and Mersenne Primes

    ERIC Educational Resources Information Center

    Ghusayni, B.

    2005-01-01

    Some examples from different areas of mathematics are explored to give a working knowledge of the computer algebra system Maple. Perfect numbers and Mersenne primes, which have fascinated people for a very long time and continue to do so, are studied using Maple and some questions are posed that still await answers.

  3. Mechanical Energy Changes in Perfectly Inelastic Collisions

    ERIC Educational Resources Information Center

    Mungan, Carl E.

    2013-01-01

    Suppose a block of mass "m"[subscript 1] traveling at speed "v"[subscript 1] makes a one-dimensional perfectly inelastic collision with another block of mass "m"[subscript 2]. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision? (Contains 1 figure.)

  4. Influence of Gender on Visual Shade Matching in Dentistry.

    PubMed

    Pecho, Oscar E; Ghinea, Razvan; Perez, Maria M; Della Bona, Alvaro

    2017-04-01

    Accuracy on visual shade matching (VSM) is one of the most difficult procedures in esthetic dentistry. Some variables can influence on this process and gender is one of the most controversial. This observational study evaluated the influence of gender on accuracy of VSM. One-hundred observers (65 females and 35 males) shade matched four human upper central incisors (UCI) to shade tabs from Vita Classical (VC) shade guide. In addition, the spectral reflectance values from the four UCI and from the 16 VC shade tabs were measured using a spectroradiometer (SP). Measurements were performed over a gray background, inside a viewing booth and under D65 illuminant (diffuse/0º geometry). CIELAB coordinates (L*, a*, and b*) were calculated according to CIE D65 illuminant and CIE 2º Standard Observer. Instrumental shade matching for each UCI, based on minimum color difference, was performed using two color difference metrics (CIELAB and CIEDE2000(2:1:1)). Data was analyzed using descriptive statistics and McNemar test (α = 0.05). Irrespective of the color difference metric, the most prevalent shade performed by females showed greater success (50% for CIELAB and 100% for CIEDE2000(2:1:1)) than males (25% for CIELAB and 50% for CIEDE2000(2:1:1)). However, such difference on gender was statistically significant only when using CIEDE2000(2:1:1) color difference metric (p ≤ 0.05). The most prevalent shade option resultant from VSM performed by females using VC shade guide perfectly agreed (100% success rate) with measurements from SP and CIEDE2000(2:1:1) color difference metric. The ability to understand and distinguish color differences in VSM is critical in clinical dentistry. Variation in shade perception due to observer gender can be minimized using additional observers and/or improving shade matching ability. (J Esthet Restor Dent 29:E15-E23, 2017). © 2017 Wiley Periodicals, Inc.

  5. Jealousy Graphs: Structure and Complexity of Decentralized Stable Matching

    DTIC Science & Technology

    2013-01-01

    reaches a µ-stable matching. This means that in expectation it will take at most nlc 4(c+1) of these transitions total before all stable components...locally perfect on that stable component. Furthermore, this process needs to be repeated no more than nlc 4(c+1) times in expectation in order for all

  6. Skyline based terrain matching

    NASA Technical Reports Server (NTRS)

    Page, Lance A.

    1990-01-01

    Skyline-based terrain matching, a new method for locating the vantage point of stereo camera or laser range-finding measurements on a global map previously prepared by satellite or aerial mapping is described. The orientation of the vantage is assumed known, but its translational parameters are determined by the algorithm. Skylines, or occluding contours, can be extracted from the sensory measurements taken by an autonomous vehicle. They can also be modeled from the global map, given a vantage estimate from which to start. The two sets of skylines, represented in cylindrical coordinates about either the true or the estimated vantage, are employed as 'features' or reference objects common to both sources of information. The terrain matching problem is formulated in terms of finding a translation between the respective representations of the skylines, by approximating the two sets of skylines as identical features (curves) on the actual terrain. The search for this translation is based on selecting the longest of the minimum-distance vectors between corresponding curves from the two sets of skylines. In successive iterations of the algorithm, the approximation that the two sets of curves are identical becomes more accurate, and the vantage estimate continues to improve. The algorithm was implemented and evaluated on a simulated terrain. Illustrations and examples are included.

  7. Renormalization group and perfect operators for stochastic differential equations.

    PubMed

    Hou, Q; Goldenfeld, N; McKane, A

    2001-03-01

    We develop renormalization group (RG) methods for solving partial and stochastic differential equations on coarse meshes. RG transformations are used to calculate the precise effect of small-scale dynamics on the dynamics at the mesh size. The fixed point of these transformations yields a perfect operator: an exact representation of physical observables on the mesh scale with minimal lattice artifacts. We apply the formalism to simple nonlinear models of critical dynamics, and show how the method leads to an improvement in the computational performance of Monte Carlo methods.

  8. We have a perfect storm - let's use it.

    PubMed

    Macleod, Hugh

    2011-01-01

    The lead paper, "Responsibility for Canada's Healthcare Quality Agenda: Interviews with Canadian Health Leaders," is a valuable contribution to the quality and safety improvement conversations taking place across the country. My commentary suggests a dramatic convergence of social, economic, demographic and technological forces has brought healthcare to a threshold of a perfect storm. To brace ourselves against this storm, I have suggested that we need to understand the system not as a structure but as relationships. I argue that alignment is not a concept that is particularly well understood - and we tend to focus almost exclusively on the component of structure.

  9. Patient HSP70-hom TG haplotype is associated with decreased transplant-related mortality and improved survival after sibling HLA-matched hematopoietic stem cell transplantation.

    PubMed

    Kim, Inho; Kim, Jin Hee; Rhee, Ji Young; Kim, Jin Won; Cho, Hyeon Jin; Cho, Eun-Young; Lee, Jong-Eun; Hong, Yun-Chul; Park, Sung Sup; Yoon, Sung-Soo; Park, Myoung Hee; Park, Seonyang; Kim, Byoung Kook

    2010-01-01

    Heat shock protein 70-hom (HSP70-hom) plays an important role in protein folding and immune responses. Therefore, HSP70-hom gene polymorphisms may act as important factors in predicting the prognosis of patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). To evaluate the role of HSP70-hom gene polymorphisms in the prognosis of patients receiving sibling human leukocyte antigen (HLA)-matched allogeneic HSCT, the HSP70-hom polymorphisms, T2437C and G2763A, were genotyped in 147 patients receiving sibling HLA-matched allogeneic HSCT. Individual diplotypes were estimated from genotype data of the two HSP70-hom polymorphisms using the expectation maximization algorithm. Patients with the 2763GG or GA genotype showed longer overall survival compared with those with the 2763AA genotype, and patients with a TG haplotype (TG/TA, TG/TG or TG/CG) also showed longer overall survival compared with those with a non-TG haplotype (TA/TA or TA/CG) (both G2763A genotype and diplotype, p<0.01). Moreover, the 2437TT genotype was found to be protective for treatment-related death compared with the 2437TC genotype, and a TG haplotype was found to be very protective for treatment-related death compared with a non-TG haplotype (T2437C genotype, p=0.04; and diplotype, p=0.02). Therefore, our results suggest that HSP70-hom polymorphisms play an important role in the prognosis of patients receiving sibling HLA-matched allogeneic HSCT.

  10. Phase- and group-matched nonlinear interactions mediated by multiple filamentation in Kerr media

    SciTech Connect

    Faccio, D.; Lotti, A.; Dubietis, A.; Tamosauskas, G.; Valiulis, G.; Piskarskas, A.; Polesana, P.; Di Trapani, P.; Couairon, A.

    2007-11-15

    Laser-pulse filamentation in Kerr media induced by a strongly elliptic input beam leads to breakup into a periodic array of filaments. In the plane of the filament array we observe strong Stokes and anti-Stokes emission at large angles. For 1 ps input pulses the measured angles are found to support two different phase-matching configurations: one nontransversally phase matched and the other perfectly phase matched. Shorter 200 fs pulses give rise to group-velocity-matched Raman conversion.

  11. The undirected incomplete perfect phylogeny problem.

    PubMed

    Satya, Ravi Vijaya; Mukherjee, Amar

    2008-01-01

    The incomplete perfect phylogeny (IPP) problem and the incomplete perfect phylogeny haplotyping (IPPH) problem deal with constructing a phylogeny for a given set of haplotypes or genotypes with missing entries. The earlier approaches for both of these problems dealt with restricted versions of the problems, where the root is either available or can be trivially re-constructed from the data, or certain assumptions were made about the data. In this paper, we deal with the unrestricted versions of the problems, where the root of the phylogeny is neither available nor trivially recoverable from the data. Both IPP and IPPH problems have previously been proven to be NP-complete. Here, we present efficient enumerative algorithms that can handle practical instances of the problem. Empirical analysis on simulated data shows that the algorithms perform very well both in terms of speed and in terms accuracy of the recovered data.

  12. [Guide to perfect prescribing in Switzerland].

    PubMed

    Arnet, Isabelle; Hersberger, Kurt E

    2014-06-01

    An important initial step in the medication process is prescription writing. The more perfect it is, the more successfully can a therapy be performed. Imprecisions and missing information lead to unnecessary queries or to errors which are often randomly discovered during a later consultation. A "perfect prescription" serves every individual involved in the medication process. The prescription document contains the instructions for the patient, the pharmacist, the nurse, and other health professionals involved in the therapy. The prescription writing process is regulated by several laws and decrees which were enacted to assure the greatest possible drug safety. Deviations from the norm may be necessary in individual cases, which require an even more responsible prescribing and explicit indication.

  13. Nonminimal coupling of perfect fluids to curvature

    SciTech Connect

    Bertolami, Orfeu; Lobo, Francisco S. N.; Paramos, Jorge

    2008-09-15

    In this work, we consider different forms of relativistic perfect fluid Lagrangian densities that yield the same gravitational field equations in general relativity (GR). A particularly intriguing example is the case with couplings of the form [1+f{sub 2}(R)]L{sub m}, where R is the scalar curvature, which induces an extra force that depends on the form of the Lagrangian density. It has been found that, considering the Lagrangian density L{sub m}=p, where p is the pressure, the extra-force vanishes. We argue that this is not the unique choice for the matter Lagrangian density, and that more natural forms for L{sub m} do not imply the vanishing of the extra force. Particular attention is paid to the impact on the classical equivalence between different Lagrangian descriptions of a perfect fluid.

  14. The erythrocyte ghost is a perfect osmometer.

    PubMed

    Kwant, W O; Seeman, P

    1970-02-01

    The osmotic swelling of intact erythrocytes in hypotonic solutions was measured using microhematocrit tubes, Van Allen tubes, and a calibrated Coulter counter. In agreement with earlier workers the intact cells did not behave as perfect osmometers, the cells swelling less than predicted by the Boyle-van't Hoff law. Erythrocyte ghosts were prepared from fresh intact erythrocytes by one-step hemolysis in 0.25% NaCl at an extremely dilute concentration of cells and the membranes were sealed at 37 degrees . The ghosts were mixed with NaCl solutions of different osmolarities and the MCV (mean cell volume) of the shrunken cells immediately monitored by a calibrated Coulter counter. It was found that the MCV values of the shrunken ghosts were accurately predicted by the Boyle-van't Hoff law. These results indicate that these erythrocyte ghosts behaved as perfect osmometers.

  15. Explaining evolution via constrained persistent perfect phylogeny.

    PubMed

    Bonizzoni, Paola; Carrieri, Anna Paola; Della Vedova, Gianluca; Trucco, Gabriella

    2014-01-01

    The perfect phylogeny is an often used model in phylogenetics since it provides an efficient basic procedure for representing the evolution of genomic binary characters in several frameworks, such as for example in haplotype inference. The model, which is conceptually the simplest, is based on the infinite sites assumption, that is no character can mutate more than once in the whole tree. A main open problem regarding the model is finding generalizations that retain the computational tractability of the original model but are more flexible in modeling biological data when the infinite site assumption is violated because of e.g. back mutations. A special case of back mutations that has been considered in the study of the evolution of protein domains (where a domain is acquired and then lost) is persistency, that is the fact that a character is allowed to return back to the ancestral state. In this model characters can be gained and lost at most once. In this paper we consider the computational problem of explaining binary data by the Persistent Perfect Phylogeny model (referred as PPP) and for this purpose we investigate the problem of reconstructing an evolution where some constraints are imposed on the paths of the tree. We define a natural generalization of the PPP problem obtained by requiring that for some pairs (character, species), neither the species nor any of its ancestors can have the character. In other words, some characters cannot be persistent for some species. This new problem is called Constrained PPP (CPPP). Based on a graph formulation of the CPPP problem, we are able to provide a polynomial time solution for the CPPP problem for matrices whose conflict graph has no edges. Using this result, we develop a parameterized algorithm for solving the CPPP problem where the parameter is the number of characters. A preliminary experimental analysis shows that the constrained persistent perfect phylogeny model allows to explain efficiently data that do not

  16. Structured metal film as a perfect absorber.

    PubMed

    Xiong, Xiang; Jiang, Shang-Chi; Hu, Yu-Hui; Peng, Ru-Wen; Wang, Mu

    2013-08-07

    A new type of absorber, a four-tined fish-spear-like resonator (FFR), constructed by the two-photon polymerization process, is reported. An absorbance of more than 90% is experimentally realized and the resonance occurs in the space between the tines. Since a continuous layer of metallic thin film covers the structure, it is perfectly thermo- and electroconductive, which is the mostly desired feature for many applications.

  17. Optimal Feedback Controlled Assembly of Perfect Crystals.

    PubMed

    Tang, Xun; Rupp, Bradley; Yang, Yuguang; Edwards, Tara D; Grover, Martha A; Bevan, Michael A

    2016-07-26

    Perfectly ordered states are targets in diverse molecular to microscale systems involving, for example, atomic clusters, protein folding, protein crystallization, nanoparticle superlattices, and colloidal crystals. However, there is no obvious approach to control the assembly of perfectly ordered global free energy minimum structures; near-equilibrium assembly is impractically slow, and faster out-of-equilibrium processes generally terminate in defective states. Here, we demonstrate the rapid and robust assembly of perfect crystals by navigating kinetic bottlenecks using closed-loop control of electric field mediated crystallization of colloidal particles. An optimal policy is computed with dynamic programming using a reaction coordinate based dynamic model. By tracking real-time stochastic particle configurations and adjusting applied fields via feedback, the evolution of unassembled particles is guided through polycrystalline states into single domain crystals. This approach to controlling the assembly of a target structure is based on general principles that make it applicable to a broad range of processes from nano- to microscales (where tuning a global thermodynamic variable yields temporal control over thermal sampling of different states via their relative free energies).

  18. How perfect is a neutron fluid?

    NASA Astrophysics Data System (ADS)

    Fu, Dan; Mekjian, Aram

    2011-04-01

    A perfect fluid has the lowest shear viscosity allowed by the uncertainty principle which also involves a study of the entropy density. Kinetic theory based on the Chapman-Enskog approach is used to obtain both the classical and quantum values of the viscosity of a neutron fluid. The interaction potential used in the study is an attractive square well with an inner hard core. The classical scattering angle and the phase shifts are calculated for this potential. The entropy density is based on the Sakur-Tetrode law plus corrections coming from two particle interactions obtained from a Beth-Ulhenbeck expression. Using these results for the viscosity and entropy density, the perfect fluid aspects of a neutron fluid are addressed. The viscosity to number density is also proportional to Planck's constant. The proportionality constant, called alpha, is found to be of the order of 1 in a quantum description of a neutron fluid. The value of the viscosity for a neutron fluid is near its unitary limit. For air at STP alpha is 7500, for water alpha is 300. The results for neutron matter suggest a near perfect fluid behavior. Supported by DOE-Grant DE-FG02Er-40987

  19. Solute drag on perfect and extended dislocations

    NASA Astrophysics Data System (ADS)

    Sills, R. B.; Cai, W.

    2016-04-01

    The drag force exerted on a moving dislocation by a field of mobile solutes is studied in the steady state. The drag force is numerically calculated as a function of the dislocation velocity for both perfect and extended dislocations. The sensitivity of the non-dimensionalized force-velocity curve to the various controlling parameters is assessed, and an approximate analytical force-velocity expression is given. A non-dimensional parameter S characterizing the strength of the solute-dislocation interaction, the background solute fraction ?, and the dislocation character angle ?, are found to have the strongest influence on the force-velocity curve. Within the model considered here, a perfect screw dislocation experiences no solute drag, but an extended screw dislocation experiences a non-zero drag force that is about 10 to 30% of the drag on an extended edge dislocation. The solutes can change the spacing between the Shockley partials in both stationary and moving extended dislocations, even when the stacking fault energy remains unaltered. Under certain conditions, the solutes destabilize an extended dislocation by either collapsing it into a perfect dislocation or causing the partials to separate unboundedly. It is proposed that the latter instability may lead to the formation of large faulted areas and deformation twins in low stacking fault energy materials containing solutes, consistent with experimental observations of copper and stainless steel containing hydrogen.

  20. Surface-enhanced Raman spectroscopy and homeland security: a perfect match?

    PubMed

    Golightly, Rebecca S; Doering, William E; Natan, Michael J

    2009-10-27

    This Nano Focus article reviews recent developments in surface-enhanced Raman spectroscopy (SERS) and its application to homeland security. It is based on invited talks given at the "Nanorods and Microparticles for Homeland Security" symposium, which was organized by one of the authors and presented at the 238th ACS National Meeting and Exhibition in Washington, DC. The three-day symposium included approximately 25 experts from academia, industry, and national laboratories and included both SERS and non-SERS approaches to detection of chemical and biological substances relevant to homeland security, as well as fundamental advances. Here, we focus on SERS and how it is uniquely positioned to have an impact in a field whose importance is increasing rapidly. We describe some technical challenges that remain and offer a glimpse of what form solutions might take.

  1. Review: artificial container-breeding mosquitoes and cemeteries: a perfect match.

    PubMed

    Vezzani, Darío

    2007-02-01

    Artificial container-breeding mosquitoes, such as Aedes aegypti, Ae. albopictus, and Culex pipiens, are well-recognized vectors of diseases throughout the world. Cemeteries are considered major sources of mosquitoes and the results of more than 30 studies concerning mosquitoes in cemeteries have been published over the last decade. The characteristics of these environments in regard to the availability of resources for mosquito development were discussed. Also, studies about early detection of Aedes vectors, ecological issues, and mosquito control performed in cemeteries were reviewed. Among 31 mosquito species found breeding in cemeteries from 16 countries, the invasive Ae. aegypti and Ae. albopictus were the most frequent ones. Species of the genus Ochlerotatus, Culex, Toxorhynchites, Culiseta, Armigeres, Lutzia, Uranotaenia, and Tripteroides were also reported. Overall, cemeteries are highly suitable habitats for artificial container-breeding mosquitoes due to the great availability of the different resources that they need (i.e. sugar substances, blood, shelter and water-filled containers). In addition, these places are mostly ideal settings to perform studies in urbanized areas because of high mosquito abundance, heterogeneity of macro- and microhabitats, and an easier access in comparison with private premises. However, the feasibility of a cemetery as a study area must be evaluated in each case considering the objectives of the study and cemetery characteristics.

  2. PERFECTLY MATCHED LAYERS FOR ELASTIC WAVES IN CYLINDRICAL AND SPHERICAL COORDINATES. (R825225)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Finding the Perfect Match: Factors That Influence Family Medicine Residency Selection.

    PubMed

    Wright, Katherine M; Ryan, Elizabeth R; Gatta, John L; Anderson, Lauren; Clements, Deborah S

    2016-04-01

    Residency program selection is a significant experience for emerging physicians, yet there is limited information about how applicants narrow their list of potential programs. This study examines factors that influence residency program selection among medical students interested in family medicine at the time of application. Medical students with an expressed interest in family medicine were invited to participate in a 37-item, online survey. Students were asked to rate factors that may impact residency selection on a 6-point Likert scale in addition to three open-ended qualitative questions. Mean values were calculated for each survey item and were used to determine a rank order for selection criteria. Logistic regression analysis was performed to identify factors that predict a strong interest in urban, suburban, and rural residency programs. Logistic regression was also used to identify factors that predict a strong interest in academic health center-based residencies, community-based residencies, and community-based residencies with an academic affiliation. A total of 705 medical students from 32 states across the country completed the survey. Location, work/life balance, and program structure (curriculum, schedule) were rated the most important factors for residency selection. Logistic regression analysis was used to refine our understanding of how each factor relates to specific types of residencies. These findings have implications for how to best advise students in selecting a residency, as well as marketing residencies to the right candidates. Refining the recruitment process will ensure a better fit between applicants and potential programs. Limited recruitment resources may be better utilized by focusing on targeted dissemination strategies.

  4. Inter-Sentential Anaphora and Coherence Relations in Discourse: A Perfect Match

    ERIC Educational Resources Information Center

    Cornish, Francis

    2009-01-01

    Hobbs [Hobbs, J.R., 1979. "Coherence and coreference." "Cognitive Science" 3, 67-90] claims that the interpretation of inter-sentential anaphors "falls out" as a "by-product" of using a particular coherence relation to integrate two discourse units. The article argues that this is only partly true. Taking the reader's perspective, I suggest that…

  5. Development of a Three Dimensional Perfectly Matched Layer for Transient Elasto-Dynamic Analyses

    DTIC Science & Technology

    2006-12-01

    dimensional analysis . Later Basu and Chopra(2004) [Ref. 14] extended the idea to a 2D transient, displacement-based, finite element (FE) method... Analysis of non-homogeneous/ anisotropic materials. • Analysis of non-linear wave phenomenon such as shock waves. The PML can be tuned to attenuate non...linear waves as well. • Conduct a time dependent analysis of an infinite waveguide using the tran- sient PML as an infinite boundary. • Examine the

  6. Text-Based Synchronous E-Learning and Dyslexia: Not Necessarily the Perfect Match!

    ERIC Educational Resources Information Center

    Woodfine, B. P.; Nunes, M. Baptista; Wright, D. J.

    2008-01-01

    The introduction, in the United Kingdom, of the Special Education Needs and Disabilities Act (SENDA) published and approved in 2001, has removed the exemptions given to educational institutions by the Disabilities Discrimination Act (DDA) of 1995. This applies to learning web sites and materials that must now undergo "reasonable…

  7. The Perfect Match: A Case Study of a First Year Woman Principal.

    ERIC Educational Resources Information Center

    Duncan, P. Kay; Seguin, Cynthia Anast; Spaulding, Wendy

    This paper presents a case study illustrating the experiences of a first-year elementary-school principal. It follows her through her 18 months on the job, and analyzes the factors contributing to her ouster. The data for the study were gathered through two interviews with the principal and interviews with five other persons in her school…

  8. Text-Based Synchronous E-Learning and Dyslexia: Not Necessarily the Perfect Match!

    ERIC Educational Resources Information Center

    Woodfine, B. P.; Nunes, M. Baptista; Wright, D. J.

    2008-01-01

    The introduction, in the United Kingdom, of the Special Education Needs and Disabilities Act (SENDA) published and approved in 2001, has removed the exemptions given to educational institutions by the Disabilities Discrimination Act (DDA) of 1995. This applies to learning web sites and materials that must now undergo "reasonable…

  9. Uniform color space based on color matching

    NASA Astrophysics Data System (ADS)

    Liao, Shih-Fang; Yang, Tsung-Hsun; Lee, Cheng-Chung

    2007-09-01

    This research intends to explore with a uniform color space based on the CIE 1931 x-y chromatic coordinate system. The goal is to improve the non-uniformity of the CIE 1931 x-y chromaticity diagram such as to approach the human color sensation as possible; however, its simple methodology still can be kept. In spite of the existence of various kinds of the uniform color coordinate systems built up early (CIE u'-v', CIE Lab, CIE LUV, etc.), the establishment of a genuine uniform color space is actually still an important work both for the basic research in color science and the practical applications of colorimetry, especially for recent growing request in illumination engineering and in display technology. In this study, the MacAdam ellipses and the Munsell color chips are utilized for the comparison with the human color sensation. One specific linear transformation matrix is found for the CIE 1931 color matching functions (see manuscript) to become the novel uniform ones. With the aid of the optimization method, the transformation matrix can be easily discovered and makes the 25 MacAdam ellipses are similar to each other in the novel uniform color space. On the other hand, the perfectiveness of the equal-hue curves and the equal-chroma contours from the Mnusell color chips evaluates for the best optimization conditions among several different definitions for the similarity of all the MacAdam ellipses. Finally, the color difference between any two colors can be simply measured by the Euclidean distance in the novel uniform color space and is still fitted to the human color sensation.

  10. One-loop operator matching in the static heavy and domain-wall light quark system with O(a) improvement

    SciTech Connect

    Ishikawa, T.; Aoki, Y.; Flynn, J.; Izubuchi, T.; Loktik, O.

    2011-05-09

    We discuss perturbative O(g{sup 2} a) matching with static heavy quarks and domain-wall light quarks for lattice operators relevant to B-meson decays and B{sup 0} - {bar B}{sup 0} mixing. The chiral symmetry of the light domain-wall quarks does not prohibit operator mixing at O(a) for these operators. The O(a) corrections to physical quantities are non-negligible and must be included to obtain high-precision simulation results for CKM physics. We provide results using plaquette, Symanzik, Iwasaki and DBW2 gluon actions and applying APE, HYP1 and HYP2 link-smearing for the static quark action.

  11. Improving the time control of the Subboreal/Subatlantic transition in a Czech peat sequence by 14C wiggle-matching

    NASA Astrophysics Data System (ADS)

    Speranza, A.; van der Plicht, J.; van Geel, B.

    2000-11-01

    To achieve an optimal time-control for a late Subboreal to early Subatlantic peat sequence from Pančavská Louka in the Czech Republic, different strategies are applied to convert a series of radiocarbon dates into a calendar time-scale. The methods of selection and preparation of the samples for AMS 14C dating are presented. The results of calibrating single radiocarbon dates are compared with a 14C wiggle-match strategy. As the accumulation rate of the peat was not constant, the concentrations of arboreal pollen are used to estimate the accumulation rate changes and to correct for these changes. The resulting time-control represents the best solution for this peat sequence with the methods currently available.

  12. Matching a Distribution by Matching Quantiles Estimation

    PubMed Central

    Sgouropoulos, Nikolaos; Yao, Qiwei; Yastremiz, Claudia

    2015-01-01

    Motivated by the problem of selecting representative portfolios for backtesting counterparty credit risks, we propose a matching quantiles estimation (MQE) method for matching a target distribution by that of a linear combination of a set of random variables. An iterative procedure based on the ordinary least-squares estimation (OLS) is proposed to compute MQE. MQE can be easily modified by adding a LASSO penalty term if a sparse representation is desired, or by restricting the matching within certain range of quantiles to match a part of the target distribution. The convergence of the algorithm and the asymptotic properties of the estimation, both with or without LASSO, are established. A measure and an associated statistical test are proposed to assess the goodness-of-match. The finite sample properties are illustrated by simulation. An application in selecting a counterparty representative portfolio with a real dataset is reported. The proposed MQE also finds applications in portfolio tracking, which demonstrates the usefulness of combining MQE with LASSO. PMID:26692592

  13. Matching a Distribution by Matching Quantiles Estimation.

    PubMed

    Sgouropoulos, Nikolaos; Yao, Qiwei; Yastremiz, Claudia

    2015-04-03

    Motivated by the problem of selecting representative portfolios for backtesting counterparty credit risks, we propose a matching quantiles estimation (MQE) method for matching a target distribution by that of a linear combination of a set of random variables. An iterative procedure based on the ordinary least-squares estimation (OLS) is proposed to compute MQE. MQE can be easily modified by adding a LASSO penalty term if a sparse representation is desired, or by restricting the matching within certain range of quantiles to match a part of the target distribution. The convergence of the algorithm and the asymptotic properties of the estimation, both with or without LASSO, are established. A measure and an associated statistical test are proposed to assess the goodness-of-match. The finite sample properties are illustrated by simulation. An application in selecting a counterparty representative portfolio with a real dataset is reported. The proposed MQE also finds applications in portfolio tracking, which demonstrates the usefulness of combining MQE with LASSO.

  14. Some Recent Results on Graph Matching,

    DTIC Science & Technology

    1987-06-01

    VJ and • work supported by ONR Contract # N00014-85-K-0488 I 1 1JI IIIII 2 the line-coloring problem [H]), there are others the polynomial -time sol...theorem of Tutte [T]. 2.1. THEOREM. A graph G has a perfect matching if and only if for every X 9_ V(G), the number of odd components of G - X is at most...here because our approach is different, being based upon the work of Edmonds, Lovasz and PuUeyblank [ELP], who gave a polynomial -time algorithm to com

  15. An almost 'perfectly' diffuse, 'perfect' reflector for far-infrared reflectance calibration

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon M.

    1993-01-01

    Specular and diffuse reflectance measurements made near normal incidence of two very rough, solid aluminum surfaces are presented for the wavelength range from 2.2 to 512 microns. The diffuse measurements made at nonspecular angles by two different detectors indicate that between 33 and 201 microns the reflectance of one surface is nearly Lambertian (isotropic) with a bidirectional reflectance distribution function (BRDF) value within 32 percent of the theoretical value of (1/pi)/sr for a perfectly diffuse, perfect reflector. Photometric reflectance spectra at the specular angle show that between 6.9 and 100 microns the specular BRDF of these surfaces is within 5 percent of the theoretical value of (1/pi)/sr. At longer wavelengths of 235, 320, and 512 microns the specular reflectance rapidly departs from that of a perfectly diffuse, perfect reflector. The two samples studied have rms surface roughnesses of 44 and 60 microns. A durable metal surface with these near perfect reflectance characteristics can be advantageously used in the FIR as a black-body source, the interior surface of an integrating sphere, and most especially as an absolute calibration standard. BRDF measurements at 40 deg incidence, though still highly diffuse, show a significant departure from Lambertian reflectance.

  16. The Perfect Aspect as a State of Being.

    ERIC Educational Resources Information Center

    Moy, Raymond H.

    English as second language (ESL) learners often avoid using the present perfect or use it improperly. In contrast with native speakers of English sampled from newspaper editorials, of whom 75 percent used the present perfect, only 22 percent of ESL college students used the present perfect correctly. This avoidance is due in part to lack of…

  17. Designing perfect linear polarization converters using perfect electric and magnetic conducting surfaces.

    PubMed

    Zhou, Gaochao; Tao, Xudong; Shen, Ze; Zhu, Guanghao; Jin, Biaobing; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng

    2016-12-13

    We propose a kind of general framework for the design of a perfect linear polarization converter that works in the transmission mode. Using an intuitive picture that is based on the method of bi-directional polarization mode decomposition, it is shown that when the device under consideration simultaneously possesses two complementary symmetry planes, with one being equivalent to a perfect electric conducting surface and the other being equivalent to a perfect magnetic conducting surface, linear polarization conversion can occur with an efficiency of 100% in the absence of absorptive losses. The proposed framework is validated by two design examples that operate near 10 GHz, where the numerical, experimental and analytic results are in good agreements.

  18. Designing perfect linear polarization converters using perfect electric and magnetic conducting surfaces

    PubMed Central

    Zhou, Gaochao; Tao, Xudong; Shen, Ze; Zhu, Guanghao; Jin, Biaobing; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng

    2016-01-01

    We propose a kind of general framework for the design of a perfect linear polarization converter that works in the transmission mode. Using an intuitive picture that is based on the method of bi-directional polarization mode decomposition, it is shown that when the device under consideration simultaneously possesses two complementary symmetry planes, with one being equivalent to a perfect electric conducting surface and the other being equivalent to a perfect magnetic conducting surface, linear polarization conversion can occur with an efficiency of 100% in the absence of absorptive losses. The proposed framework is validated by two design examples that operate near 10 GHz, where the numerical, experimental and analytic results are in good agreements. PMID:27958313

  19. Explaining evolution via constrained persistent perfect phylogeny

    PubMed Central

    2014-01-01

    Background The perfect phylogeny is an often used model in phylogenetics since it provides an efficient basic procedure for representing the evolution of genomic binary characters in several frameworks, such as for example in haplotype inference. The model, which is conceptually the simplest, is based on the infinite sites assumption, that is no character can mutate more than once in the whole tree. A main open problem regarding the model is finding generalizations that retain the computational tractability of the original model but are more flexible in modeling biological data when the infinite site assumption is violated because of e.g. back mutations. A special case of back mutations that has been considered in the study of the evolution of protein domains (where a domain is acquired and then lost) is persistency, that is the fact that a character is allowed to return back to the ancestral state. In this model characters can be gained and lost at most once. In this paper we consider the computational problem of explaining binary data by the Persistent Perfect Phylogeny model (referred as PPP) and for this purpose we investigate the problem of reconstructing an evolution where some constraints are imposed on the paths of the tree. Results We define a natural generalization of the PPP problem obtained by requiring that for some pairs (character, species), neither the species nor any of its ancestors can have the character. In other words, some characters cannot be persistent for some species. This new problem is called Constrained PPP (CPPP). Based on a graph formulation of the CPPP problem, we are able to provide a polynomial time solution for the CPPP problem for matrices whose conflict graph has no edges. Using this result, we develop a parameterized algorithm for solving the CPPP problem where the parameter is the number of characters. Conclusions A preliminary experimental analysis shows that the constrained persistent perfect phylogeny model allows to

  20. Design optimization of nanostrip metamaterial perfect absorbers

    NASA Astrophysics Data System (ADS)

    El-Aasser, Mostafa A.

    2014-01-01

    Metamaterial perfect absorber (MPA) promises many applications due to its capability of complete suppression of transmission or/and reflection. The complete dissipation of the incident electromagnetic energy by the absorptive meta-atoms makes it a unique candidate in many photonic and optoelectronic devices. An ultrathin metamaterial absorber that consists of a periodic nanostrip metal on top of a planar dielectric slab backed by a conducting metal plate is presented. The spectral absorptivity of MPA is investigated by the finite difference time domain method from visible to near-infrared. The various geometrical and material parameters of MPA are optimized for maximum absorption.

  1. The Travelling Salesman Polytope and (0,2)-Matchings.

    DTIC Science & Technology

    1981-02-01

    characterizing those graphs having perfect 1-mat- chings is the following: Theorem 2.8 ( Tutte [16]). G has a perfect 1 -matching if and only if for every...graphs is polynomially equivalent to the more general problem. An interestinz feature of the results of the previous sections is that they do apply... Tutte , "The factorization of linear graphs", Journal of the London Mathematical Society 22 (1947) 107-111. LI a . n Ud nt.. . R E A D - REj) i E3ORT

  2. Block Matching for Object Tracking

    SciTech Connect

    Gyaourova, A; Kamath, C; Cheung, S

    2003-10-13

    Models which describe road traffic patterns can be helpful in detection and/or prevention of uncommon and dangerous situations. Such models can be built by the use of motion detection algorithms applied to video data. Block matching is a standard technique for encoding motion in video compression algorithms. We explored the capabilities of the block matching algorithm when applied for object tracking. The goal of our experiments is two-fold: (1) to explore the abilities of the block matching algorithm on low resolution and low frame rate video and (2) to improve the motion detection performance by the use of different search techniques during the process of block matching. Our experiments showed that the block matching algorithm yields good object tracking results and can be used with high success on low resolution and low frame rate video data. We observed that different searching methods have small effect on the final results. In addition, we proposed a technique based on frame history, which successfully overcame false motion caused by small camera movements.

  3. Broadband gradient impedance matching using an acoustic metamaterial for ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Li, Zheng; Yang, Dan-Qing; Liu, Shi-Lei; Yu, Si-Yuan; Lu, Ming-Hui; Zhu, Jie; Zhang, Shan-Tao; Zhu, Ming-Wei; Guo, Xia-Sheng; Wu, Hao-Dong; Wang, Xin-Long; Chen, Yan-Feng

    2017-02-01

    High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding -6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems.

  4. Broadband gradient impedance matching using an acoustic metamaterial for ultrasonic transducers.

    PubMed

    Li, Zheng; Yang, Dan-Qing; Liu, Shi-Lei; Yu, Si-Yuan; Lu, Ming-Hui; Zhu, Jie; Zhang, Shan-Tao; Zhu, Ming-Wei; Guo, Xia-Sheng; Wu, Hao-Dong; Wang, Xin-Long; Chen, Yan-Feng

    2017-02-17

    High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding -6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems.

  5. Broadband gradient impedance matching using an acoustic metamaterial for ultrasonic transducers

    PubMed Central

    Li, Zheng; Yang, Dan-Qing; Liu, Shi-Lei; Yu, Si-Yuan; Lu, Ming-Hui; Zhu, Jie; Zhang, Shan-Tao; Zhu, Ming-Wei; Guo, Xia-Sheng; Wu, Hao-Dong; Wang, Xin-Long; Chen, Yan-Feng

    2017-01-01

    High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding −6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems. PMID:28211510

  6. Mining a database of single amplified genomes from Red Sea brine pool extremophiles—improving reliability of gene function prediction using a profile and pattern matching algorithm (PPMA)

    PubMed Central

    Grötzinger, Stefan W.; Alam, Intikhab; Ba Alawi, Wail; Bajic, Vladimir B.; Stingl, Ulrich; Eppinger, Jörg

    2014-01-01

    Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs) and poor homology of novel extremophile's genomes pose significant challenges for the attribution of functions to the coding sequences identified. The anoxic deep-sea brine pools of the Red Sea are a promising source of novel enzymes with unique evolutionary adaptation. Sequencing data from Red Sea brine pool cultures and SAGs are annotated and stored in the Integrated Data Warehouse of Microbial Genomes (INDIGO) data warehouse. Low sequence homology of annotated genes (no similarity for 35% of these genes) may translate into false positives when searching for specific functions. The Profile and Pattern Matching (PPM) strategy described here was developed to eliminate false positive annotations of enzyme function before progressing to labor-intensive hyper-saline gene expression and characterization. It utilizes InterPro-derived Gene Ontology (GO)-terms (which represent enzyme function profiles) and annotated relevant PROSITE IDs (which are linked to an amino acid consensus pattern). The PPM algorithm was tested on 15 protein families, which were selected based on scientific and commercial potential. An initial list of 2577 enzyme commission (E.C.) numbers was translated into 171 GO-terms and 49 consensus patterns. A subset of INDIGO-sequences consisting of 58 SAGs from six different taxons of bacteria and archaea were selected from six different brine pool environments. Those SAGs code for 74,516 genes, which were independently scanned for the GO-terms (profile filter) and PROSITE IDs (pattern filter). Following stringent reliability filtering, the non-redundant hits (106 profile hits and 147 pattern hits) are classified as reliable, if at least two relevant descriptors (GO-terms and/or consensus patterns) are present. Scripts for annotation, as well as for the PPM algorithm, are available

  7. Mining a database of single amplified genomes from Red Sea brine pool extremophiles-improving reliability of gene function prediction using a profile and pattern matching algorithm (PPMA).

    PubMed

    Grötzinger, Stefan W; Alam, Intikhab; Ba Alawi, Wail; Bajic, Vladimir B; Stingl, Ulrich; Eppinger, Jörg

    2014-01-01

    Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs) and poor homology of novel extremophile's genomes pose significant challenges for the attribution of functions to the coding sequences identified. The anoxic deep-sea brine pools of the Red Sea are a promising source of novel enzymes with unique evolutionary adaptation. Sequencing data from Red Sea brine pool cultures and SAGs are annotated and stored in the Integrated Data Warehouse of Microbial Genomes (INDIGO) data warehouse. Low sequence homology of annotated genes (no similarity for 35% of these genes) may translate into false positives when searching for specific functions. The Profile and Pattern Matching (PPM) strategy described here was developed to eliminate false positive annotations of enzyme function before progressing to labor-intensive hyper-saline gene expression and characterization. It utilizes InterPro-derived Gene Ontology (GO)-terms (which represent enzyme function profiles) and annotated relevant PROSITE IDs (which are linked to an amino acid consensus pattern). The PPM algorithm was tested on 15 protein families, which were selected based on scientific and commercial potential. An initial list of 2577 enzyme commission (E.C.) numbers was translated into 171 GO-terms and 49 consensus patterns. A subset of INDIGO-sequences consisting of 58 SAGs from six different taxons of bacteria and archaea were selected from six different brine pool environments. Those SAGs code for 74,516 genes, which were independently scanned for the GO-terms (profile filter) and PROSITE IDs (pattern filter). Following stringent reliability filtering, the non-redundant hits (106 profile hits and 147 pattern hits) are classified as reliable, if at least two relevant descriptors (GO-terms and/or consensus patterns) are present. Scripts for annotation, as well as for the PPM algorithm, are available

  8. Sublithographic Architecture: Shifting the Responsibility for Perfection

    NASA Astrophysics Data System (ADS)

    Dehon, A.

    In the past, processing had orders of magnitude between devices and atoms (e.g., with silicon atom lattice spacing around 0.5 nm, a minimum size feature was roughly 2000 atoms wide when we had 1 μm feature sizes). It was the process engineer's job to craft this large collection of atoms into "perfect" devices. The circuit designer and architect could then design systems knowing the process engineer would always give them a set of perfect devices. As we continue to shrink our devices, we no longer have orders of magnitude between the devices and the atoms. As a result, the circuit designers and architects are beginning to work within a similar realm of atoms. Consequently, they must assume some of the responsibilities for dealing with atomic-scale imperfections and uncertainty. This demands a significant shift in our abstraction hierarchy, the responsibilities and expectations at each level in this hierarchy, our fabrication techniques, our testing strategies, and our approaches to design for these atomic-scale computing systems.

  9. Metamaterial perfect absorber based hot electron photodetection.

    PubMed

    Li, Wei; Valentine, Jason

    2014-06-11

    While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems.

  10. Achieving global perfect homeostasis through transporter regulation

    PubMed Central

    Springer, Michael

    2017-01-01

    Nutrient homeostasis—the maintenance of relatively constant internal nutrient concentrations in fluctuating external environments—is essential to the survival of most organisms. Transcriptional regulation of plasma membrane transporters by internal nutrient concentrations is typically assumed to be the main mechanism by which homeostasis is achieved. While this mechanism is homeostatic we show that it does not achieve global perfect homeostasis—a condition where internal nutrient concentrations are completely independent of external nutrient concentrations for all external nutrient concentrations. We show that the criterion for global perfect homeostasis is that transporter levels must be inversely proportional to net nutrient flux into the cell and that downregulation of active transporters (activity-dependent regulation) is a simple and biologically plausible mechanism that meets this criterion. Activity-dependent transporter regulation creates a trade-off between robustness and efficiency, i.e., the system's ability to withstand perturbation in external nutrients and the transporter production rate needed to maintain homeostasis. Additionally, we show that a system that utilizes both activity-dependent transporter downregulation and regulation of transporter synthesis by internal nutrient levels can create a system that mitigates the shortcomings of each of the individual mechanisms. This analysis highlights the utility of activity-dependent regulation in achieving homeostasis and calls for a re-examination of the mechanisms of regulation of other homeostatic systems. PMID:28414718

  11. Predicting perfect adaptation motifs in reaction kinetic networks.

    PubMed

    Drengstig, Tormod; Ueda, Hiroki R; Ruoff, Peter

    2008-12-25

    Adaptation and compensation mechanisms are important to keep organisms fit in a changing environment. "Perfect adaptation" describes an organism's response to an external stepwise perturbation by resetting some of its variables precisely to their original preperturbation values. Examples of perfect adaptation are found in bacterial chemotaxis, photoreceptor responses, or MAP kinase activities. Two concepts have evolved for how perfect adaptation may be understood. In one approach, so-called "robust perfect adaptation", the adaptation is a network property (due to integral feedback control), which is independent of rate constant values. In the other approach, which we have termed "nonrobust perfect adaptation", a fine-tuning of rate constant values is needed to show perfect adaptation. Although integral feedback describes robust perfect adaptation in general terms, it does not directly show where in a network perfect adaptation may be observed. Using control theoretic methods, we are able to predict robust perfect adaptation sites within reaction kinetic networks and show that a prerequisite for robust perfect adaptation is that the network is open and irreversible. We applied the method on various reaction schemes and found that new (robust) perfect adaptation motifs emerge when considering suggested models of bacterial and eukaryotic chemotaxis.

  12. Power drainage and energy dissipation in lossy but perfect lenses

    NASA Astrophysics Data System (ADS)

    Rosenblatt, Gilad; Orenstein, Meir

    2017-05-01

    It has recently been shown that passive lens designs can retain perfect lensing despite intrinsic loss in the comprising left-handed materials. Here we show that energy conservation is not at odds with the operation of such lossy perfect lenses: The irreversible transfer of electromagnetic power to the lossy material dictates that a smaller portion of the power emitted by the source arrives at the image, but image fidelity remains absolute. Moreover, the power that does arrive at the perfect image must drain from the system there. This is shown to apply to any layered perfect lens based on left-handed media, including the well-known Veselago lens. Combined with what is known about Maxwell's fisheye lens, our results suggest that power drainage is universal to all perfect lenses and is intrinsic to any perfect image. Properly addressing this unique power dynamics is therefore essential to any successful realization of practical perfect lenses with existing metamaterials.

  13. Efficient nonlinear generation of high power, higher order, ultrafast "perfect" vortices in green.

    PubMed

    Apurv Chaitanya, N; Jabir, M V; Samanta, G K

    2016-04-01

    We report on efficient nonlinear generation of ultrafast, higher order "perfect" vortices at the green wavelength. Based on Fourier transformation of the higher order Bessel-Gauss (BG) beam generated through the combination of the spiral phase plate and axicon, we have transformed the Gaussian beam of the ultrafast Yb-fiber laser at 1060 nm into perfect vortices of power 4.4 W and order up to 6. Using single-pass second-harmonic generation (SHG) of such vortices in 5 mm long chirped MgO-doped, periodically poled congruent LiNbO3 crystal, we have generated perfect vortices at green wavelength (530 nm) with output power of 1.2 W and vortex order up to 12 at a single-pass conversion efficiency of 27%, independent of the orders. This is the highest single-pass SHG efficiency of any optical beams other than Gaussian beams. Unlike the disintegration of higher order vortices due to spatial walk-off effect in birefringent crystals, here, the use of the quasi-phase-matching process enables generation of high-quality vortices, even at higher orders. The green perfect vortices of all orders have temporal and spectral widths of 507 fs and 1.9 nm, respectively, corresponding to a time-bandwidth product of 1.02.

  14. Improved Detection Limit in Rapid Detection of Human Enterovirus 71 and Coxsackievirus A16 by a Novel Reverse Transcription–Isothermal Multiple-Self-Matching-Initiated Amplification Assay

    PubMed Central

    Ding, Xiong; Nie, Kai; Shi, Lei; Zhang, Yong; Guan, Li; Zhang, Dan

    2014-01-01

    Rapid detection of human enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) is important in the early phase of hand-foot-and-mouth disease (HFMD). In this study, we developed and evaluated a novel reverse transcription–isothermal multiple-self-matching-initiated amplification (RT-IMSA) assay for the rapid detection of EV71 and CVA16 by use of reverse transcriptase, together with a strand displacement DNA polymerase. Real-time RT-IMSA assays using a turbidimeter and visual RT-IMSA assays to detect EV71 and CVA16 were established and completed in 1 h, and the reported corresponding real-time reverse transcription–loop-mediated isothermal amplification (RT-LAMP) assays targeting the same regions of the VP1 gene were adopted as parallel tests. Through testing VP1 RNAs transcribed in vitro, the real-time RT-IMSA assays exhibited better linearity of quantification, with R2 values of 0.952 (for EV71) and 0.967 (for CVA16), than the real-time RT-LAMP assays, which had R2 values of 0.803 (for EV71) and 0.904 (for CVA16). Additionally, the detection limits of the real-time RT-IMSA assays (approximately 937 for EV71 and 67 for CVA16 copies/reaction) were higher than those of real-time RT-LAMP assays (approximately 3,266 for EV71 and 430 for CVA16 copies/reaction), and similar results were observed in the visual RT-IMSA assays. The new approaches also possess high specificities for the corresponding targets, with no cross-reactivity observed. In clinical assessment, compared to commercial reverse transcription-quantitative PCR (qRT-PCR) kits, the diagnostic sensitivities of the real-time RT-IMSA assays (96.4% for EV71 and 94.6% for CVA16) were higher than those of the real-time RT-LAMP assays (91.1% for EV71 and 90.8% for CVA16). The visual RT-IMSA assays also exhibited the same results. In conclusion, this proof-of-concept study suggests that the novel RT-IMSA assay is superior to the RT-LAMP assay in terms of detection limit and has the potential to rapidly detect EV71

  15. Ontology Matching Across Domains

    DTIC Science & Technology

    2010-05-01

    matching include GMO [1], Anchor-Prompt [2], and Similarity Flooding [3]. GMO is an iterative structural matcher, which uses RDF bipartite graphs to...AFRL under contract# FA8750-09-C-0058. References [1] Hu, W., Jian, N., Qu, Y., Wang, Y., “ GMO : a graph matching for ontologies”, in: Proceedings of

  16. DOE Matching Grant Program

    SciTech Connect

    Dr Marvin Adams

    2002-03-01

    OAK 270 - The DOE Matching Grant Program provided $50,000.00 to the Dept of N.E. at TAMU, matching a gift of $50,000.00 from TXU Electric. The $100,000.00 total was spent on scholarships, departmental labs, and computing network.

  17. Innovative Writing Instruction: Practice Makes Perfect! Realizing Classrooms as "Landscapes of Learning," Not Places of Perfection

    ERIC Educational Resources Information Center

    Ozier, Lance

    2011-01-01

    Pressure for students to produce writing perfection in the classroom often eclipses the emphasis placed on the need for students to practice writing. Occasions for students to choose, challenge, and reflect--to actually risk risking--are too often absent from conversations among students and teachers in countless English classrooms. Tom Romano…

  18. Innovative Writing Instruction: Practice Makes Perfect! Realizing Classrooms as "Landscapes of Learning," Not Places of Perfection

    ERIC Educational Resources Information Center

    Ozier, Lance

    2011-01-01

    Pressure for students to produce writing perfection in the classroom often eclipses the emphasis placed on the need for students to practice writing. Occasions for students to choose, challenge, and reflect--to actually risk risking--are too often absent from conversations among students and teachers in countless English classrooms. Tom Romano…

  19. Improving late Holocene radiocarbon-based chronologies by matching paleomagnetic secular variations to geomagnetic field models - Examples from Nam Co (Tibet) and Lake Kalimpaa (Sulawesi)

    NASA Astrophysics Data System (ADS)

    Haberzettl, T.; Kasper, T.; St-Onge, G.; Behling, H.; Daut, G.; Doberschütz, S.; Kirleis, W.; Mäusbacher, R.; Nowaczyk, N.

    2010-12-01

    were chosen for age-depth modeling and a linear interpolation was applied. Subsequently, inclination, declination and intensity were compared to the CALS3k.3 model also showing an excellent match from ~1350 cal BP to the present. Although, the age-depth models of both lakes are conservative, comparisons of paleomagnetic data with geomagnetic spherical harmonic models support this approach. This leads to the conclusion that the presented chronologies are suited for further paleoenvironmental investigations. This is important as both areas lack well-dated records. On the other hand, our data also support the validity of the CALS-models for the past ~4000 and ~1350 cal BP on the Tibetan Plateau and Indonesia, where paleomagnetic data are very scarce.

  20. Use of a bilayer lattice-matched AlInGaN barrier for improving the channel carrier confinement of enhancement-mode AlInGaN/GaN hetero-structure field-effect transistors

    NASA Astrophysics Data System (ADS)

    Rahbardar Mojaver, Hassan; Gosselin, Jean-Lou; Valizadeh, Pouya

    2017-06-01

    A quaternary lattice-matched layer structure based on employing a bilayer barrier for improving the carrier confinement in the channel of enhancement-mode metal-face c-plane wurtzite AlInGaN/GaN hetero-structure field effect transistors (HFETs) is for the first time proposed. Using the commercial self-consistent Poisson-Schrödinger solver Nextnano, electronic properties of the proposed hetero-structure, including the sheet charge density and carrier confinement on the GaN side of the hetero-interface, are evaluated. Based on these evaluations, it is shown that while the proposed layer structure substantially improves the carrier confinement in the GaN channel layer, it also upholds the merits of employing a lattice-matched barrier towards achieving an enhancement-mode operation (i.e., in the absence of the piezoelectric effect). According to these simulations, in terms of maintaining the required positive threshold-voltage for the enhancement-mode operation, it is also shown that the proposed layer structure substantially outperforms the quaternary AlInGaN/GaN HFETs employing a thin AlN spacer layer.

  1. Match graph generation for symbolic indirect correlation

    NASA Astrophysics Data System (ADS)

    Lopresti, Daniel; Nagy, George; Joshi, Ashutosh

    2006-01-01

    Symbolic indirect correlation (SIC) is a new approach for bringing lexical context into the recognition of unsegmented signals that represent words or phrases in printed or spoken form. One way of viewing the SIC problem is to find the correspondence, if one exists, between two bipartite graphs, one representing the matching of the two lexical strings and the other representing the matching of the two signal strings. While perfect matching cannot be expected with real-world signals and while some degree of mismatch is allowed for in the second stage of SIC, such errors, if they are too numerous, can present a serious impediment to a successful implementation of the concept. In this paper, we describe a framework for evaluating the effectiveness of SIC match graph generation and examine the relatively simple, controlled cases of synthetic images of text strings typeset, both normally and in highly condensed fashion. We quantify and categorize the errors that arise, as well as present a variety of techniques we have developed to visualize the intermediate results of the SIC process.

  2. A perfect launch of Space Shuttle Discovery

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Space Shuttle Discovery lifts off Launch Pad 39A against a backdrop of xenon lights (just above the orbiter' nose and at left). On the Mobile Launcher Platform beneath, water begins flooding the area for flame and sound control. The perfect on- time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.

  3. The failure strengths of perfect diamond crystals

    NASA Technical Reports Server (NTRS)

    Whitlock, J.; Ruoff, A. L.

    1981-01-01

    Finite elasticity analysis is extended to the 110 direction, where off axis strain symmetry is not present, and the third order elastic data are obtained for diamond. The compressive yield strengths of perfect diamond crystals loaded in the 100, 110, and 111 directions are predicted to be 2.2, 5.6, and 2.8 Mbars, respectively, while the corresponding tensile fracture strengths are 1.0, 0.5, and 0.5 Mbars. From these results and from Hertz theory it is predicted that ring fracture of spherically tipped diamonds pressed against a flat will occur at pressures of 1.8-1.9 Mbars, substantially below the yield pressure (above 3 Mbars). Modification of the tip shape leads to a predicted increase in the pressure at which fracture occurs.

  4. A perfect launch viewed across Banana Creek

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Space Shuttle Discovery seems to burst forth from a pillow of smoke as it lifts off from Launch Pad 39A on mission STS-92 to the International Space Station. The brilliant light from the solid rocket booster flames is reflected in nearby water. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.

  5. A perfect launch viewed across Banana Creek

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Billows of smoke and steam surround Space Shuttle Discovery as it lifts off from Launch Pad 39A on mission STS-92 to the International Space Station. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.

  6. A perfect launch viewed across Banana Creek

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Billows of smoke and steam surround Space Shuttle Discovery as it lifts off from Launch Pad 39A on mission STS-92 to the International Space Station. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.

  7. A perfect launch viewed across Banana Creek

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Space Shuttle Discovery seems to burst forth from a pillow of smoke as it lifts off from Launch Pad 39A on mission STS-92 to the International Space Station. The brilliant light from the solid rocket booster flames is reflected in nearby water. The perfect on-time liftoff occurred at 7:17 p.m. EDT, sending a crew of seven on the 100th launch in the history of the Shuttle program. Discovery carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery's landing is expected Oct. 22 at 2:10 p.m. EDT.

  8. Electromagnetic Detection of a Perfect Carpet Cloak

    NASA Astrophysics Data System (ADS)

    Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile

    2015-05-01

    It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics.

  9. Haplotyping as perfect phylogeny: a direct approach.

    PubMed

    Bafna, Vineet; Gusfield, Dan; Lancia, Giuseppe; Yooseph, Shibu

    2003-01-01

    A full haplotype map of the human genome will prove extremely valuable as it will be used in large-scale screens of populations to associate specific haplotypes with specific complex genetic-influenced diseases. A haplotype map project has been announced by NIH. The biological key to that project is the surprising fact that some human genomic DNA can be partitioned into long blocks where genetic recombination has been rare, leading to strikingly fewer distinct haplotypes in the population than previously expected (Helmuth, 2001; Daly et al., 2001; Stephens et al., 2001; Friss et al., 2001). In this paper we explore the algorithmic implications of the no-recombination in long blocks observation, for the problem of inferring haplotypes in populations. This assumption, together with the standard population-genetic assumption of infinite sites, motivates a model of haplotype evolution where the haplotypes in a population are assumed to evolve along a coalescent, which as a rooted tree is a perfect phylogeny. We consider the following algorithmic problem, called the perfect phylogeny haplotyping problem (PPH), which was introduced by Gusfield (2002) - given n genotypes of length m each, does there exist a set of at most 2n haplotypes such that each genotype is generated by a pair of haplotypes from this set, and such that this set can be derived on a perfect phylogeny? The approach taken by Gusfield (2002) to solve this problem reduces it to established, deep results and algorithms from matroid and graph theory. Although that reduction is quite simple and the resulting algorithm nearly optimal in speed, taken as a whole that approach is quite involved, and in particular, challenging to program. Moreover, anyone wishing to fully establish, by reading existing literature, the correctness of the entire algorithm would need to read several deep and difficult papers in graph and matroid theory. However, as stated by Gusfield (2002), many simplifications are possible and the

  10. Electromagnetic detection of a perfect carpet cloak.

    PubMed

    Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile

    2015-05-22

    It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics.

  11. Electromagnetic Detection of a Perfect Carpet Cloak

    PubMed Central

    Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile

    2015-01-01

    It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798

  12. Recent Results from RHIC: The Perfect Liquid

    SciTech Connect

    Westfall, Gary

    2006-07-19

    In the past two years we have witnessed a leap forward in the understanding high temperature, high density, and strongly interacting matter produced in ultra-relativistic heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Combining measurements of Au+Au, d+Au, and p+p collisions at energies up to 200 GeV per nucleon pair in the center of mass frame, the four RHIC experimental groups, STAR, PHENIX, PHOBOS, and BRAHMS, have produced impressive experimental evidence for the existence of a new form of matter. In this Colloquium, I will present an overview of recent experimental results from RHIC including evidence for thermalization, hydrodynamic behavior of a perfect fluid, the partonic origin of flow, and jet suppression. These measurements point to the observation of a hot, dense, strongly interacting matter produced in central Au+Au collisions at the highest available energies.

  13. An approach towards a perfect thermal diffuser

    PubMed Central

    Vemuri, Krishna P.; Bandaru, Prabhakar R.

    2016-01-01

    A method for the most efficient removal of heat, through an anisotropic composite, is proposed. It is shown that a rational placement of constituent materials, in the radial and the azimuthal directions, at a given point in the composite yields a uniform temperature distribution in spherical diffusers. Such arrangement is accompanied by a very significant reduction of the source temperature, in principle, to infinitesimally above the ambient temperature and forms the basis for the design of a perfect thermal diffuser with maximal heat dissipation. Orders of magnitude enhanced performance, compared to that obtained through the use of a diffuser constituted from a single material with isotropic thermal conductivity has been observed and the analytical principles underlying the design were validated through extensive computational simulations. PMID:27404569

  14. LensPerfect Analysis of Abell 1689

    NASA Astrophysics Data System (ADS)

    Coe, Dan A.

    2007-12-01

    I present the first massmap to perfectly reproduce the position of every gravitationally-lensed multiply-imaged galaxy detected to date in ACS images of Abell 1689. This massmap was obtained using a powerful new technique made possible by a recent advance in the field of Mathematics. It is the highest resolution assumption-free Dark Matter massmap to date, with the resolution being limited only by the number of multiple images detected. We detect 8 new multiple image systems and identify multiple knots in individual galaxies to constrain a grand total of 168 knots within 135 multiple images of 42 galaxies. No assumptions are made about mass tracing light, and yet the brightest visible structures in A1689 are reproduced in our massmap, a few with intriguing positional offsets. Our massmap probes radii smaller than that resolvable in current Dark Matter simulations of galaxy clusters. And at these radii, we observe slight deviations from the NFW and Sersic profiles which describe simulated Dark Matter halos so well. While we have demonstrated that our method is able to recover a known input massmap (to limited resolution), further tests are necessary to determine the uncertainties of our mass profile and positions of massive subclumps. I compile the latest weak lensing data from ACS, Subaru, and CFHT, and attempt to fit a single profile, either NFW or Sersic, to both the observed weak and strong lensing. I confirm the finding of most previous authors, that no single profile fits extremely well to both simultaneously. Slight deviations are revealed, with the best fits slightly over-predicting the mass profile at both large and small radius. Our easy-to-use software, called LensPerfect, will be made available soon. This research was supported by the European Commission Marie Curie International Reintegration Grant 017288-BPZ and the PNAYA grant AYA2005-09413-C02.

  15. Improving Elementary School Quality Through the Use of a Social-Emotional and Character Development Program: A Matched-Pair, Cluster-Randomized, Controlled Trial in Hawai’i

    PubMed Central

    Snyder, Frank J.; Vuchinich, Samuel; Acock, Alan; Washburn, Isaac J.; Flay, Brian R.

    2012-01-01

    BACKGROUND School safety and quality affect student learning and success. This study examined the effects of a comprehensive elementary school-wide social-emotional and character education program, Positive Action, on teacher, parent, and student perceptions of school safety and quality utilizing a matched-pair, cluster-randomized, controlled design. The Positive Action Hawai’i trial included 20 racially/ethnically diverse schools and was conducted from 2002–2003 through 2005–2006. METHODS School-level archival data, collected by the Hawai’i Department of Education, were used to examine program effects at 1-year post-trial. Teacher, parent, and student data were analyzed to examine indicators of school quality such as student safety and well-being, involvement, and satisfaction, as well as overall school quality. Matched-paired t-tests were used for the primary analysis, and sensitivity analyses included permutation tests and random-intercept growth curve models. RESULTS Analyses comparing change from baseline to 1-year post-trial revealed that intervention schools demonstrated significantly improved school quality compared to control schools, with 21%, 13%, and 16% better overall school quality scores as reported by teachers, parents, and students, respectively. Teacher, parent, and student reports on individual school-quality indicators showed improvement in student safety and well-being, involvement, satisfaction, quality student support, focused and sustained action, standards-based learning, professionalism and system capacity, and coordinated team work. Teacher reports also showed an improvement in the responsiveness of the system. CONCLUSIONS School quality was substantially improved, providing evidence that a school-wide social-emotional and character education program can enhance school quality and facilitate whole-school change. PMID:22142170

  16. Design principles for infrared wide-angle perfect absorber based on plasmonic structure.

    PubMed

    Pu, Mingbo; Hu, Chenggang; Wang, Min; Huang, Cheng; Zhao, Zeyu; Wang, Changtao; Feng, Qin; Luo, Xiangang

    2011-08-29

    An approach for designing a wide-angle perfect absorber at infrared frequencies is proposed. The technique is based on a perfectly impedance-matched sheet (PIMS) formed by plasmonic nanostructure. It is shown that the effective impedance is more physical meaningful and beneficial than effective medium in describing the electromagnetic properties of metamaterial absorber. As a specific implementation of this technique, a wide-angle polarization-independent dual-band absorber is numerically demonstrated at frequencies of 100THz and 280THz with absorption close to 100% simultaneously. Circuit models are utilized to describe the impedance property of localized plasmon modes and the results show good agreement with that retrieved from reflection coefficient at normal incidence.

  17. Do musicians with perfect pitch have more autism traits than musicians without perfect pitch? An empirical study.

    PubMed

    Dohn, Anders; Garza-Villarreal, Eduardo A; Heaton, Pamela; Vuust, Peter

    2012-01-01

    Perfect pitch, also known as absolute pitch (AP), refers to the rare ability to identify or produce a musical tone correctly without the benefit of an external reference. AP is often considered to reflect musical giftedness, but it has also been associated with certain disabilities due to increased prevalence of AP in individuals with sensory and developmental disorders. Here, we determine whether individual autistic traits are present in people with AP. We quantified subclinical levels of autism traits using the Autism-Spectrum Quotient (AQ) in three matched groups of subjects: 16 musicians with AP (APs), 18 musicians without AP (non-APs), and 16 non-musicians. In addition, we measured AP ability by a pitch identification test with sine wave tones and piano tones. We found a significantly higher degree of autism traits in APs than in non-APs and non-musicians, and autism scores were significantly correlated with pitch identification scores (r = .46, p = .003). However, our results showed that APs did not differ from non-APs on diagnostically crucial social and communicative domain scores and their total AQ scores were well below clinical thresholds for autism. Group differences emerged on the imagination and attention switching subscales of the AQ. Thus, whilst these findings do link AP with autism, they also show that AP ability is most strongly associated with personality traits that vary widely within the normal population.

  18. Do Musicians with Perfect Pitch Have More Autism Traits than Musicians without Perfect Pitch? An Empirical Study

    PubMed Central

    Dohn, Anders; Garza-Villarreal, Eduardo A.; Heaton, Pamela; Vuust, Peter

    2012-01-01

    Perfect pitch, also known as absolute pitch (AP), refers to the rare ability to identify or produce a musical tone correctly without the benefit of an external reference. AP is often considered to reflect musical giftedness, but it has also been associated with certain disabilities due to increased prevalence of AP in individuals with sensory and developmental disorders. Here, we determine whether individual autistic traits are present in people with AP. We quantified subclinical levels of autism traits using the Autism-Spectrum Quotient (AQ) in three matched groups of subjects: 16 musicians with AP (APs), 18 musicians without AP (non-APs), and 16 non-musicians. In addition, we measured AP ability by a pitch identification test with sine wave tones and piano tones. We found a significantly higher degree of autism traits in APs than in non-APs and non-musicians, and autism scores were significantly correlated with pitch identification scores (r = .46, p = .003). However, our results showed that APs did not differ from non-APs on diagnostically crucial social and communicative domain scores and their total AQ scores were well below clinical thresholds for autism. Group differences emerged on the imagination and attention switching subscales of the AQ. Thus, whilst these findings do link AP with autism, they also show that AP ability is most strongly associated with personality traits that vary widely within the normal population. PMID:22666425

  19. Good match exploration for infrared face recognition

    NASA Astrophysics Data System (ADS)

    Yang, Changcai; Zhou, Huabing; Sun, Sheng; Liu, Renfeng; Zhao, Ji; Ma, Jiayi

    2014-11-01

    Establishing good feature correspondence is a critical prerequisite and a challenging task for infrared (IR) face recognition. Recent studies revealed that the scale invariant feature transform (SIFT) descriptor outperforms other local descriptors for feature matching. However, it only uses local appearance information for matching, and hence inevitably leads to a number of false matches. To address this issue, this paper explores global structure information (GSI) among SIFT correspondences, and proposes a new method SIFT-GSI for good match exploration. This is achieved by fitting a smooth mapping function for the underlying correct matches, which involves softassign and deterministic annealing. Quantitative comparisons with state-of-the-art methods on a publicly available IR human face database demonstrate that SIFT-GSI significantly outperforms other methods for feature matching, and hence it is able to improve the reliability of IR face recognition systems.

  20. Conformal and traversable wormholes with monopole and perfect fluid in f(R)-gravity

    NASA Astrophysics Data System (ADS)

    Taşer, Doǧukan; Doǧru, Melis Ulu

    2016-10-01

    We investigate spherically symmetric spacetime filled with global monopole and perfect fluid in f(R)-gravity. We consider field equations of f(R)-gravity in order to understand the global monopole and the perfect fluid curve to the spacetime. It has taken advantages of conformal symmetry properties of the spacetime to solve these equations. The obtained solutions are improved in case of phantom energy. It is shown that obtained f(R) function is consistent with well-known models of the modified gravity. Also, it is examined whether the obtained solutions support a traversable wormhole geometry. Obtained results of the solutions have been concluded.

  1. Rethinking the Match: A Proposal for Modern Match-Making.

    PubMed

    Ray, Chris; Bishop, Steven E; Dow, Alan W

    2017-06-27

    Since the 1950s, the National Resident Matching Program, or "the Match," has governed the placement of medical students into residencies. The Match was created to protect students in an era when residency positions outnumbered applicants and hospitals pressured students early in their academic careers to commit to a residency position. Now, however, applicants outnumber positions, applicants are applying to increasing numbers of programs, and the costs of the Match for applicants and programs are high. Meanwhile, medical education is evolving toward a competency-based approach, a U.S. physician shortage is predicted, and some researchers describe a "July effect"-worse clinical outcomes correlated with the mass entry of new residents.Against this background, the authors argue for adopting a more modern, free-market approach to residency match-making that might better suit the needs of applicants, programs, and the public. They propose allowing students who have been identified by their medical schools as having achieved graduation-level competency to apply to residency programs at any point during the year. Residency programs would set their own application timetables and extend offers in an ongoing fashion. Students, counseled by their schools, would accept or decline offers as desired. The authors argue this approach would better support competency-based education while allowing applicants and programs more choice regarding how they engage and adapt within the selection process. The approach's staggered start times for new residents might attenuate the July effect and improve outcomes for patients. Medical students might also enter and thereby complete residency earlier, increasing the physician workforce.

  2. Pediatric MATCH Infographic

    Cancer.gov

    Infographic explaining NCI-COG Pediatric MATCH, a cancer treatment clinical trial for children and adolescents, from 1 to 21 years of age, that is testing the use of precision medicine for pediatric cancers.

  3. Project Matching Initiative

    EPA Pesticide Factsheets

    The Green Power Partnership's Project Matching initiative works to connect green power users with new, not-yet-built renewable energy projects that may align with their energy, environmental, and financial objectives.

  4. Cognitive Levels Matching.

    ERIC Educational Resources Information Center

    Brooks, Martin; And Others

    1983-01-01

    The Cognitive Levels Matching Project trains teachers to guide students' skill acquisition and problem-solving processes by assessing students' cognitive levels and adapting their teaching materials accordingly. (MLF)

  5. DOE Matching Grant Program

    SciTech Connect

    Tsoukalas, L.

    2002-12-31

    Funding used to support a portion of the Nuclear Engineering Educational Activities. Upgrade of teaching labs, student support to attend professional conferences, salary support for graduate students. The US Department of Energy (DOE) has funded Purdue University School of Nuclear Engineering during the period of five academic years covered in this report starting in the academic year 1996-97 and ending in the academic year 2000-2001. The total amount of funding for the grant received from DOE is $416K. In the 1990's, Nuclear Engineering Education in the US experienced a significant slow down. Student enrollment, research support, number of degrees at all levels (BS, MS, and PhD), number of accredited programs, University Research and Training Reactors, all went through a decline to alarmingly low levels. Several departments closed down, while some were amalgamated with other academic units (Mechanical Engineering, Chemical Engineering, etc). The School of Nuclear Engineering at Purdue University faced a major challenge when in the mid 90's our total undergraduate enrollment for the Sophomore, Junior and Senior Years dropped in the low 30's. The DOE Matching Grant program greatly strengthened Purdue's commitment to the Nuclear Engineering discipline and has helped to dramatically improve our undergraduate and graduate enrollment, attract new faculty and raise the School of Nuclear Engineering status within the University and in the National scene (our undergraduate enrollment has actually tripled and stands at an all time high of over 90 students; total enrollment currently exceeds 110 students). In this final technical report we outline and summarize how the grant was expended at Purdue University.

  6. The molecular matching problem

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1993-01-01

    Molecular chemistry contains many difficult optimization problems that have begun to attract the attention of optimizers in the Operations Research community. Problems including protein folding, molecular conformation, molecular similarity, and molecular matching have been addressed. Minimum energy conformations for simple molecular structures such as water clusters, Lennard-Jones microclusters, and short polypeptides have dominated the literature to date. However, a variety of interesting problems exist and we focus here on a molecular structure matching (MSM) problem.

  7. Metasurface perfect absorber based on guided resonance of a photonic hypercrystal

    NASA Astrophysics Data System (ADS)

    Chang, You-Chia; Kildishev, Alexander V.; Narimanov, Evgenii E.; Norris, Theodore B.

    2016-10-01

    By exploiting the guided resonance of a photonic hypercrystal—a periodic structure that combines the properties of hyperbolic materials and photonic crystals—we numerically demonstrate a perfect absorber consisting of a photonic hypercrystal slab, a dielectric spacer, and a back reflector. The guided resonance of the photonic hypercrystal slab creates a field enhancement and confinement within a deep subwavelength thickness; therefore, the ultrathin photonic hypercrystal slab serves as a two-dimensional resonator that can be treated accurately as a metasurface. We show that the perfect absorber is equivalent to a metasurface Salisbury screen, where the metasurface formed by the photonic hypercrystal slab provides the appropriate electric sheet conductivity required for critical coupling. We also present examples of combining the perfect absorber with graphene to make optical modulators and to improve the absorption in graphene photodetectors.

  8. Magnetic safety matches

    NASA Astrophysics Data System (ADS)

    Lindén, J.; Lindberg, M.; Greggas, A.; Jylhävuori, N.; Norrgrann, H.; Lill, J. O.

    2017-07-01

    In addition to the main ingredients; sulfur, potassium chlorate and carbon, ordinary safety matches contain various dyes, glues etc, giving the head of the match an even texture and appealing color. Among the common reddish-brown matches there are several types, which after ignition can be attracted by a strong magnet. Before ignition the match head is generally not attracted by the magnet. An elemental analysis based on proton-induced x-ray emission was performed to single out iron as the element responsible for the observed magnetism. 57Fe Mössbauer spectroscopy was used for identifying the various types of iron-compounds, present before and after ignition, responsible for the macroscopic magnetism: Fe2O3 before and Fe3O4 after. The reaction was verified by mixing the main chemicals in the match-head with Fe2O3 in glue and mounting the mixture on a match stick. The ash residue after igniting the mixture was magnetic.

  9. Coherent perfect absorption and reflection in slow-light waveguides.

    PubMed

    Gutman, Nadav; Sukhorukov, Andrey A; Chong, Y D; de Sterke, C Martijn

    2013-12-01

    We identify a family of unusual slow-light modes occurring in lossy multimode grating waveguides, for which either the forward or backward mode components, or both, are degenerate. In the fully degenerate case, the response can be modulated between coherent perfect absorption (zero reflection) and perfect reflection by varying the wave amplitudes in a uniform input waveguide. The perfectly absorbed wave has anomalously short absorption length, scaling as the inverse one-third power of the absorptivity.

  10. Will a perfect model agree with perfect observations? The impact of spatial sampling

    NASA Astrophysics Data System (ADS)

    Schutgens, Nick A. J.; Gryspeerdt, Edward; Weigum, Natalie; Tsyro, Svetlana; Goto, Daisuke; Schulz, Michael; Stier, Philip

    2016-05-01

    The spatial resolution of global climate models with interactive aerosol and the observations used to evaluate them is very different. Current models use grid spacings of ˜ 200 km, while satellite observations of aerosol use so-called pixels of ˜ 10 km. Ground site or airborne observations relate to even smaller spatial scales. We study the errors incurred due to different resolutions by aggregating high-resolution simulations (10 km grid spacing) over either the large areas of global model grid boxes ("perfect" model data) or small areas corresponding to the pixels of satellite measurements or the field of view of ground sites ("perfect" observations). Our analysis suggests that instantaneous root-mean-square (RMS) differences of perfect observations from perfect global models can easily amount to 30-160 %, for a range of observables like AOT (aerosol optical thickness), extinction, black carbon mass concentrations, PM2.5, number densities and CCN (cloud condensation nuclei). These differences, due entirely to different spatial sampling of models and observations, are often larger than measurement errors in real observations. Temporal averaging over a month of data reduces these differences more strongly for some observables (e.g. a threefold reduction for AOT), than for others (e.g. a twofold reduction for surface black carbon concentrations), but significant RMS differences remain (10-75 %). Note that this study ignores the issue of temporal sampling of real observations, which is likely to affect our present monthly error estimates. We examine several other strategies (e.g. spatial aggregation of observations, interpolation of model data) for reducing these differences and show their effectiveness. Finally, we examine consequences for the use of flight campaign data in global model evaluation and show that significant biases may be introduced depending on the flight strategy used.

  11. Results from the VALUE perfect predictor experiment: process-based evaluation

    NASA Astrophysics Data System (ADS)

    Maraun, Douglas; Soares, Pedro; Hertig, Elke; Brands, Swen; Huth, Radan; Cardoso, Rita; Kotlarski, Sven; Casado, Maria; Pongracz, Rita; Bartholy, Judit

    2016-04-01

    Until recently, the evaluation of downscaled climate model simulations has typically been limited to surface climatologies, including long term means, spatial variability and extremes. But these aspects are often, at least partly, tuned in regional climate models to match observed climate. The tuning issue is of course particularly relevant for bias corrected regional climate models. In general, a good performance of a model for these aspects in present climate does therefore not imply a good performance in simulating climate change. It is now widely accepted that, to increase our condidence in climate change simulations, it is necessary to evaluate how climate models simulate relevant underlying processes. In other words, it is important to assess whether downscaling does the right for the right reason. Therefore, VALUE has carried out a broad process-based evaluation study based on its perfect predictor experiment simulations: the downscaling methods are driven by ERA-Interim data over the period 1979-2008, reference observations are given by a network of 85 meteorological stations covering all European climates. More than 30 methods participated in the evaluation. In order to compare statistical and dynamical methods, only variables provided by both types of approaches could be considered. This limited the analysis to conditioning local surface variables on variables from driving processes that are simulated by ERA-Interim. We considered the following types of processes: at the continental scale, we evaluated the performance of downscaling methods for positive and negative North Atlantic Oscillation, Atlantic ridge and blocking situations. At synoptic scales, we considered Lamb weather types for selected European regions such as Scandinavia, the United Kingdom, the Iberian Pensinsula or the Alps. At regional scales we considered phenomena such as the Mistral, the Bora or the Iberian coastal jet. Such process-based evaluation helps to attribute biases in surface

  12. Fast image matching algorithm based on projection characteristics

    NASA Astrophysics Data System (ADS)

    Zhou, Lijuan; Yue, Xiaobo; Zhou, Lijun

    2011-06-01

    Based on analyzing the traditional template matching algorithm, this paper identified the key factors restricting the speed of matching and put forward a brand new fast matching algorithm based on projection. Projecting the grayscale image, this algorithm converts the two-dimensional information of the image into one-dimensional one, and then matches and identifies through one-dimensional correlation, meanwhile, because of normalization has been done, when the image brightness or signal amplitude increasing in proportion, it could also perform correct matching. Experimental results show that the projection characteristics based image registration method proposed in this article could greatly improve the matching speed, which ensuring the matching accuracy as well.

  13. Latent palmprint matching.

    PubMed

    Jain, Anil K; Feng, Jianjiang

    2009-06-01

    The evidential value of palmprints in forensic applications is clear as about 30 percent of the latents recovered from crime scenes are from palms. While biometric systems for palmprint-based personal authentication in access control type of applications have been developed, they mostly deal with low-resolution (about 100 ppi) palmprints and only perform full-to-full palmprint matching. We propose a latent-to-full palmprint matching system that is needed in forensic applications. Our system deals with palmprints captured at 500 ppi (the current standard in forensic applications) or higher resolution and uses minutiae as features to be compatible with the methodology used by latent experts. Latent palmprint matching is a challenging problem because latent prints lifted at crime scenes are of poor image quality, cover only a small area of the palm, and have a complex background. Other difficulties include a large number of minutiae in full prints (about 10 times as many as fingerprints), and the presence of many creases in latents and full prints. A robust algorithm to reliably estimate the local ridge direction and frequency in palmprints is developed. This facilitates the extraction of ridge and minutiae features even in poor quality palmprints. A fixed-length minutia descriptor, MinutiaCode, is utilized to capture distinctive information around each minutia and an alignment-based minutiae matching algorithm is used to match two palmprints. Two sets of partial palmprints (150 live-scan partial palmprints and 100 latent palmprints) are matched to a background database of 10,200 full palmprints to test the proposed system. Despite the inherent difficulty of latent-to-full palmprint matching, rank-1 recognition rates of 78.7 and 69 percent, respectively, were achieved in searching live-scan partial palmprints and latent palmprints against the background database.

  14. Total transmission of airborne sound by impedance-matched ultra-thin metasurfaces

    NASA Astrophysics Data System (ADS)

    Tang, Weipeng; Ren, Chunyu

    2017-03-01

    Acoustic labyrinthine metamaterials are particularly effective for constructing acoustic metasurfaces owing to their extreme refractive index. However, an evident drawback of these coiling-up structures is their large impedance mismatch with incident waves, causing less than optimal results. In this paper, we show that the intractable impedance mismatching problem can be solved by spatially tailoring the geometry of the labyrinthine metamaterial units and hence their effective constitutive parameters. These optimized units simultaneously exhibit a tunable refractive index up to 7 and a perfect impedance match with air; thus, as building units, they show potential for improving the performance of acoustic metasurface-based applications. Applying these deep-subwavelength units in anomalous refraction and an acoustic antenna, we demonstrate that the new optimized acoustic labyrinthine metamaterial-based design scheme shows extraordinary beam-steering effects, and more importantly, it provides extremely high transmission efficiency with a smaller size than existing designs.

  15. Self-Impedance-Matched Hall-Effect Gyrators and Circulators

    NASA Astrophysics Data System (ADS)

    Bosco, S.; Haupt, F.; DiVincenzo, D. P.

    2017-02-01

    We present a model study of an alternative implementation of a two-port Hall-effect microwave gyrator. Our setup involves three electrodes, one of which acts as a common ground for the others. Based on the capacitive-coupling model of Viola and DiVincenzo, we analyze the performance of the device and we predict that ideal gyration can be achieved at specific frequencies. Interestingly, the impedance of the three-terminal gyrator can be made arbitrarily small for certain coupling strengths, so that no auxiliary impedance matching is required. Although the bandwidth of the device shrinks as the impedance decreases, it can be improved by reducing the magnetic field; it can be realistically increased up to 150 MHz at 50 Ω by working at the filling factor ν =10 . We also examine the effects of the parasitic capacitive coupling between electrodes and we find that, although, in general, they strongly influence the response of device, their effect is negligible at low impedance. Finally, we analyze an interferometric implementation of a circulator, which incorporates the gyrator in a Mach-Zender-like construction. Perfect circulation in both directions can be achieved, depending on frequency and on the details of the interferometer.

  16. Computing the Casimir energy using the point-matching method

    SciTech Connect

    Lombardo, F. C.; Mazzitelli, F. D.; Vazquez, M.; Villar, P. I.

    2009-09-15

    We use a point-matching approach to numerically compute the Casimir interaction energy for a two perfect-conductor waveguide of arbitrary section. We present the method and describe the procedure used to obtain the numerical results. At first, our technique is tested for geometries with known solutions, such as concentric and eccentric cylinders. Then, we apply the point-matching technique to compute the Casimir interaction energy for new geometries such as concentric corrugated cylinders and cylinders inside conductors with focal lines.

  17. Perfect terahertz absorber using fishnet based metafilm

    SciTech Connect

    Azad, Abul Kalam; Shchegolkov, Dmitry Yu; Chen, Houtong; Taylor, Antoinette; Smirnova, E I; O' Hara, John F

    2009-01-01

    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  18. Hypothesis: A perfect day conveys internal time.

    PubMed

    Groß, J V; Fritschi, L; Erren, T C

    2017-04-01

    In 2007 the International Agency for Research on Cancer [IARC] concluded "shift work that involves circadian disruption is probably carcinogenic to humans" (Group 2A). To investigate the "probable" causal link, information on individual chronobiology is needed to specify exposures to circadian disruption associated with shift work. In epidemiological studies this information is usually assessed by questionnaire. The most widely used Morningness-Eveningness-Questionnaire (MEQ) and MunichChronoTypeQuestionnaire (MCTQ) reveal information on circadian type (MEQ) and actual sleep behaviour (MCTQ). As a further option we suggest to obtain preferred sleep times by using what we call the perfect day (PD) approach. We hypothesize that a PD - as a day of completely preferred sleep behaviour - captures pristine internal time. We argue that the PD approach may measure internal time more accurately than the MEQ and MCTQ which convey influences by work and social time pressures. The PD approach may therefore reduce misclassifications of internal time and reveal circadian disruption caused by different shift systems.

  19. Matching forensic sketches to mug shot photos.

    PubMed

    Klare, Brendan F; Li, Zhifeng; Jain, Anil K

    2011-03-01

    The problem of matching a forensic sketch to a gallery of mug shot images is addressed in this paper. Previous research in sketch matching only offered solutions to matching highly accurate sketches that were drawn while looking at the subject (viewed sketches). Forensic sketches differ from viewed sketches in that they are drawn by a police sketch artist using the description of the subject provided by an eyewitness. To identify forensic sketches, we present a framework called local feature-based discriminant analysis (LFDA). In LFDA, we individually represent both sketches and photos using SIFT feature descriptors and multiscale local binary patterns (MLBP). Multiple discriminant projections are then used on partitioned vectors of the feature-based representation for minimum distance matching. We apply this method to match a data set of 159 forensic sketches against a mug shot gallery containing 10,159 images. Compared to a leading commercial face recognition system, LFDA offers substantial improvements in matching forensic sketches to the corresponding face images. We were able to further improve the matching performance using race and gender information to reduce the target gallery size. Additional experiments demonstrate that the proposed framework leads to state-of-the-art accuracys when matching viewed sketches.

  20. PUMA: The Positional Update and Matching Algorithm

    NASA Astrophysics Data System (ADS)

    Line, J. L. B.; Webster, R. L.; Pindor, B.; Mitchell, D. A.; Trott, C. M.

    2017-01-01

    We present new software to cross-match low-frequency radio catalogues: the Positional Update and Matching Algorithm. The Positional Update and Matching Algorithm combines a positional Bayesian probabilistic approach with spectral matching criteria, allowing for confusing sources in the matching process. We go on to create a radio sky model using Positional Update and Matching Algorithm based on the Murchison Widefield Array Commissioning Survey, and are able to automatically cross-match 98.5% of sources. Using the characteristics of this sky model, we create simple simulated mock catalogues on which to test the Positional Update and Matching Algorithm, and find that Positional Update and Matching Algorithm can reliably find the correct spectral indices of sources, along with being able to recover ionospheric offsets. Finally, we use this sky model to calibrate and remove foreground sources from simulated interferometric data, generated using OSKAR (the Oxford University visibility generator). We demonstrate that there is a substantial improvement in foreground source removal when using higher frequency and higher resolution source positions, even when correcting positions by an average of 0.3 arcmin given a synthesised beam-width of 2.3 arcmin.

  1. Indexing Volumetric Shapes with Matching and Packing.

    PubMed

    Koes, David Ryan; Camacho, Carlos J

    2015-04-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X.

  2. Indexing Volumetric Shapes with Matching and Packing

    PubMed Central

    Koes, David Ryan; Camacho, Carlos J.

    2014-01-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X. PMID:26085707

  3. Cross-matching within the Chandra Source Catalog

    NASA Astrophysics Data System (ADS)

    Rots, Arnold H.; Burke, Douglas J.; Civano, Francesca; Hain, Roger; Nguyen, Dan

    2017-01-01

    Cross-matching among overlapping source detections in the development of the Chandra Source Catalog (CSC) presents considerable challenges, since the Point Spread Function (PSF) of the Chandra X-ray Observatory varies significantly over the field of view. For the production of the second release of the CSC we have developed a cross-match tool that is based on the Bayesian algorithms by Budavari, Heinis, and Szalay (ApJ 679, 301 and 705, 739), making use of the error ellipses for the derived positions of the detections.However, calculating match probabilities only on the basis of error ellipses breaks down when the PSFs are significantly different. This is an issue that is not commonly addressed in cross-match tools. We have applied a satisfactory modification to the algorithm that, although not perfect, ameliorates the issue for the vast majority of such cases.A separate issue is that as the number of overlapping detections increases, the number of matches to be considered increases at an alarming rate, requiring procedural adjustments to ensure that the cross-matching finishes within a Hubble time.We intend to make the tool available as a general purpose cross-match engine for calculating match probabilities between sources in multiple catalogs simultaneously.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  4. Cross-matching with the Chandra Source Catalog

    NASA Astrophysics Data System (ADS)

    Rots, Arnold H.; Nguyen, Dan; Budavari, Tamas; Burke, Douglas J.; Civano, Francesca M.; Hain, Roger

    2017-08-01

    Cross-matching the Chandra Source Catalog (CSC) with other catalogs presents considerable challenges, since the Point Spread Function (PSF) of the Chandra X-ray Observatory varies significantly over the field of view. For the second release of the CSC we have developed a cross-match tool that is based on the Bayesian algorithms by Budavari, Heinis, and Szalay (ApJ 679, 301 and 705, 739), making use of the error ellipses for the derived positions of the detections.However, calculating match probabilities only on the basis of error ellipses breaks down when the PSFs are significantly different. Not only can bonafide matches easily be missed, but the scene is also muddied by ambiguous multiple matches. These are issues that are not commonly addressed in cross-match tools. We have applied a satisfactory modification to the algorithm that, although not perfect, ameliorates the problems for the vast majority of such cases.A separate issue is that as the number of overlapping catalogs increases, the number of matches to be considered increases at an alarming rate, requiring procedural adjustments to ensure that the cross-matching finishes within a Hubble time. We have found a solution among graph theory algorithms.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  5. A multiband perfect absorber based on hyperbolic metamaterials.

    PubMed

    Sreekanth, Kandammathe Valiyaveedu; ElKabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R; Gurkan, Umut A; Strangi, Giuseppe

    2016-05-18

    In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors.

  6. A multiband perfect absorber based on hyperbolic metamaterials

    PubMed Central

    Sreekanth, Kandammathe Valiyaveedu; ElKabbash, Mohamed; Alapan, Yunus; Rashed, Alireza R.; Gurkan, Umut A.; Strangi, Giuseppe

    2016-01-01

    In recent years, considerable research efforts have been focused on near-perfect and perfect light absorption using metamaterials spanning frequency ranges from microwaves to visible frequencies. This relatively young field is currently facing many challenges that hampers its possible practical applications. In this paper, we present grating coupled-hyperbolic metamaterials (GC-HMM) as multiband perfect absorber that can offer extremely high flexibility in engineering the properties of electromagnetic absorption. The fabricated GC-HMMs exhibit several highly desirable features for technological applications such as polarization independence, wide angle range, broad- and narrow- band modes, multiband perfect and near perfect absorption in the visible to near-IR and mid-IR spectral range. In addition, we report a direct application of the presented system as an absorption based plasmonic sensor with a record figure of merit for this class of sensors. PMID:27188789

  7. Lattice fluid dynamics from perfect discretizations of continuum flows

    SciTech Connect

    Katz, E.; Wiese, U.

    1998-11-01

    We use renormalization group methods to derive equations of motion for large scale variables in fluid dynamics. The large scale variables are averages of the underlying continuum variables over cubic volumes and naturally exist on a lattice. The resulting lattice dynamics represents a perfect discretization of continuum physics, i.e., grid artifacts are completely eliminated. Perfect equations of motion are derived for static, slow flows of incompressible, viscous fluids. For Hagen-Poiseuille flow in a channel with a square cross section the equations reduce to a perfect discretization of the Poisson equation for the velocity field with Dirichlet boundary conditions. The perfect large scale Poisson equation is used in a numerical simulation and is shown to represent the continuum flow exactly. For nonsquare cross sections one can use a numerical iterative procedure to derive flow equations that are approximately perfect. {copyright} {ital 1998} {ital The American Physical Society}

  8. A New Approach for Semantic Web Matching

    NASA Astrophysics Data System (ADS)

    Zamanifar, Kamran; Heidary, Golsa; Nematbakhsh, Naser; Mardukhi, Farhad

    In this work we propose a new approach for semantic web matching to improve the performance of Web Service replacement. Because in automatic systems we should ensure the self-healing, self-configuration, self-optimization and self-management, all services should be always available and if one of them crashes, it should be replaced with the most similar one. Candidate services are advertised in Universal Description, Discovery and Integration (UDDI) all in Web Ontology Language (OWL). By the help of bipartite graph, we did the matching between the crashed service and a Candidate one. Then we chose the best service, which had the maximum rate of matching. In fact we compare two services' functionalities and capabilities to see how much they match. We found that the best way for matching two web services, is comparing the functionalities of them.

  9. Tuned perfect prognostication forecasts of mesoscale snowfall for southern Ontario

    NASA Astrophysics Data System (ADS)

    Burrows, William R.

    1990-02-01

    A procedure for producing site-specific 1- and 2-day categorical forecasts of 24-hour accumulated snowfall by statistical forecast methods has been developed and tested for a small area of Ontario adjacent to southern Georgian Bay. A perfect prognosis ("perfect prog," or PP) method was used, with predictors designed to handle lake-effect and nonlake-effect snowfall. Predictors were selected from a basic set of potential predictors by a stepwise multiple discriminant analysis (MDA) procedure done in three stages, where the third stage involved adding functions of predictors already selected in the first two stages to the basic predictor set. The third stage appears to enhance the discriminating power of the original predictor set because the number of "hits" of snowfall forecasts made with independent data was significantly increased and the distribution of forecasts was brought closer to the observed distribution. A two-step, rule-based tuning procedure was applied to the PP-MDA forecasts to help compensate for errors that arise when the PP-MDA statistical equations are used with numerical weather prediction model data, and for errors that arise from the conservative nature of MDA forecasts. A rule-based nonparametric statistical classification procedure (CART) was used in the first step. When the rules for tuning forecasts were tested with independent data, CART was found to increase the skill of the tuned forecasts, particularly in the common categories (1,2), and to improve the reliability of category 1 forecasts at a majority of the stations. However, CART was unable to find rules for infrequent and rare snow categories. Step B of the tuning procedure, a semicomputerized manual search for additional rules not seen by CART, was undertaken in an attempt to "do something" about this problem. When tested with independent data, overall improvement was found in the skill of forecasts tuned by two-step procedure, but it was too small to make an appreciable difference

  10. Electrodynamics analysis on coherent perfect absorber and phase-controlled optical switch.

    PubMed

    Chen, Tianjie; Duan, Shaoguang; Chen, Y C

    2012-05-01

    A coherent perfect absorber is essentially a specially designed Fabry-Perot interferometer, which completely extinguishes the incident coherent light. The one- and two-beam coherent perfect absorbers have been analyzed using classical electrodynamics by considering index matching in layered structures to totally suppress reflections. This approach presents a clear and physically intuitive picture for the principle of operation of a perfect absorber. The results show that the incident beam(s) must have correct phases and amplitudes, and the real and imaginary parts of the refractive indices of the media in the interferometer must satisfy a well-defined relation. Our results are in agreement with those obtained using the S-matrix analysis. However, the results were obtained solely based on the superposition of waves from multiple reflections without invoking the concept of time reversal as does the S-matrix approach. Further analysis shows that the two-beam device can be configured to function as a phase-controlled three-state switch.

  11. Is Matching Innate?

    ERIC Educational Resources Information Center

    Gallistel, C. R.; King, Adam Philip; Gottlieb, Daniel; Balci, Fuat; Papachristos, Efstathios B.; Szalecki, Matthew; Carbone, Kimberly S.

    2007-01-01

    Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling.…

  12. Dewey Concentration Match.

    ERIC Educational Resources Information Center

    School Library Media Activities Monthly, 1996

    1996-01-01

    Giving students a chance to associate numbers with subjects can be useful in speeding their location of desired print or nonprint materials and helping students feel independent when browsing. A matching game for helping students learn the Dewey numbers is presented. Instructions for the library media specialist or teacher, instructions for…

  13. School Match Revisited.

    ERIC Educational Resources Information Center

    Lynch, Mary Jo; Weeks, Ann

    1988-01-01

    Reports an interview with the director of School Match, a firm that has created a database of information on public and private schools to assist relocated families in identifying the best local schools. The firm's finding that library and media services' expenditures relates most significantly to student achievement is discussed. (CLB)

  14. Is Matching Innate?

    ERIC Educational Resources Information Center

    Gallistel, C. R.; King, Adam Philip; Gottlieb, Daniel; Balci, Fuat; Papachristos, Efstathios B.; Szalecki, Matthew; Carbone, Kimberly S.

    2007-01-01

    Experimentally naive mice matched the proportions of their temporal investments (visit durations) in two feeding hoppers to the proportions of the food income (pellets per unit session time) derived from them in three experiments that varied the coupling between the behavioral investment and food income, from no coupling to strict coupling.…

  15. Inter-image matching

    NASA Technical Reports Server (NTRS)

    Wolfe, R. H., Jr.; Juday, R. D.

    1982-01-01

    Interimage matching is the process of determining the geometric transformation required to conform spatially one image to another. In principle, the parameters of that transformation are varied until some measure of some difference between the two images is minimized or some measure of sameness (e.g., cross-correlation) is maximized. The number of such parameters to vary is faily large (six for merely an affine transformation), and it is customary to attempt an a priori transformation reducing the complexity of the residual transformation or subdivide the image into small enough match zones (control points or patches) that a simple transformation (e.g., pure translation) is applicable, yet large enough to facilitate matching. In the latter case, a complex mapping function is fit to the results (e.g., translation offsets) in all the patches. The methods reviewed have all chosen one or both of the above options, ranging from a priori along-line correction for line-dependent effects (the high-frequency correction) to a full sensor-to-geobase transformation with subsequent subdivision into a grid of match points.

  16. Derivatives of Matching.

    ERIC Educational Resources Information Center

    Herrnstein, R. J.

    1979-01-01

    The matching law for reinforced behavior solves a differential equation relating infinitesimal changes in behavior to infinitesimal changes in reinforcement. The equation expresses plausible conceptions of behavior and reinforcement, yields a simple nonlinear operator model for acquisition, and suggests a alternative to the economic law of…

  17. [Propensity score matching in SPSS].

    PubMed

    Huang, Fuqiang; DU, Chunlin; Sun, Menghui; Ning, Bing; Luo, Ying; An, Shengli

    2015-11-01

    To realize propensity score matching in PS Matching module of SPSS and interpret the analysis results. The R software and plug-in that could link with the corresponding versions of SPSS and propensity score matching package were installed. A PS matching module was added in the SPSS interface, and its use was demonstrated with test data. Score estimation and nearest neighbor matching was achieved with the PS matching module, and the results of qualitative and quantitative statistical description and evaluation were presented in the form of a graph matching. Propensity score matching can be accomplished conveniently using SPSS software.

  18. Matched designs and causal diagrams

    PubMed Central

    Mansournia, Mohammad A; Hernán, Miguel A; Greenland, Sander

    2013-01-01

    We use causal diagrams to illustrate the consequences of matching and the appropriate handling of matched variables in cohort and case-control studies. The matching process generally forces certain variables to be independent despite their being connected in the causal diagram, a phenomenon known as unfaithfulness. We show how causal diagrams can be used to visualize many previous results about matched studies. Cohort matching can prevent confounding by the matched variables, but censoring or other missing data and further adjustment may necessitate control of matching variables. Case-control matching generally does not prevent confounding by the matched variables, and control of matching variables may be necessary even if those were not confounders initially. Matching on variables that are affected by the exposure and the outcome, or intermediates between the exposure and the outcome, will ordinarily produce irremediable bias. PMID:23918854

  19. Matching current windstorms to historical analogues

    NASA Astrophysics Data System (ADS)

    Becker, Bernd; Maisey, Paul; Scannell, Claire; Vanvyve, Emilie; Mitchell, Lorna; Steptoe, Hamish

    2015-04-01

    assessment of the goodness of fit made by the rank proximity measure. Using this technique a series of potential historical footprints matching the current footprint is found. Each potential match is indexed according to its closeness to the current footprint where an index rating of 0 is a perfect match or "identical twin". Such pattern matching of current and forecast windstorms against an historical archive can enable insurers estimate a rapid prediction of likely loss and aid the timely deployment of staff and funds at the right level.

  20. Computer code for determination of thermally perfect gas properties

    NASA Technical Reports Server (NTRS)

    Witte, David W.; Tatum, Kenneth E.

    1994-01-01

    A set of one-dimensional compressible flow relations for a thermally perfect, calorically imperfect gas is derived for the specific heat c(sub p), expressed as a polynomial function of temperature, and developed into the thermally perfect gas (TPG) computer code. The code produces tables of compressible flow properties similar to those of NACA Rep. 1135. Unlike the tables of NACA Rep. 1135 which are valid only in the calorically perfect temperature regime, the TPG code results are also valid in the thermally perfect calorically imperfect temperature regime which considerably extends the range of temperature application. Accuracy of the TPG code in the calorically perfect temperature regime is verified by comparisons with the tables of NACA Rep. 1135. In the thermally perfect, calorically imperfect temperature regime, the TPG code is validated by comparisons with results obtained from the method of NACA Rep. 1135 for calculating the thermally perfect calorically imperfect compressible flow properties. The temperature limits for application of the TPG code are also examined. The advantage of the TPG code is its applicability to any type of gas (monatomic, diatomic, triatomic, or polyatomic) or any specified mixture thereof, whereas the method of NACA Rep. 1135 is restricted to only diatomic gases.

  1. Kaizen and ergonomics: the perfect marriage.

    PubMed

    Rodriguez, Martin Antonio; Lopez, Luis Fernando

    2012-01-01

    This paper is an approach of how Kaizen (Continuous Improvement) and Ergonomics could be implemented in the field of work. The Toyota's Team Members are the owners of this job, applying tools and techniques to improve work conditions using the Kaizen Philosophy in a QCC Activity (Quality Control Circle).

  2. Matching controlled vocabulary words.

    PubMed

    Grabar, Natalia; Zweigenbaum, Pierre; Soualmia, Lina; Darmoni, Stéfan

    2003-01-01

    This study examines an enabling condition for natural languages access to medical knowledge resources (Medline, CISMeF) indexed with controlled vocabularies (e.g., the MeSH): is the vocabulary of user queries comparable with that of the index terms? The two vocabularies were compared in their original form, then under incrementally normalized forms, using character-based normalizations then linguistic normalizations. Only 16.7% of the user vocabulary, in its original form, is in the MeSH. Progressive normalizations increase this proportion to 65.5%. Besides, if the frequencies of occurrence of words are taken into account, 89.3% of user word occurrences can be matched to MeSH words. This shows the interest of taking into account further matching methods between queries and index terms than those presented here.

  3. Surface matching via currents.

    PubMed

    Vaillant, Marc; Glaunès, Joan

    2005-01-01

    We present a new method for computing an optimal deformation between two arbitrary surfaces embedded in Euclidean 3-dimensional space. Our main contribution is in building a norm on the space of surfaces via representation by currents of geometric measure theory. Currents are an appropriate choice for representations because they inherit natural transformation properties from differential forms. We impose a Hilbert space structure on currents, whose norm gives a convenient and practical way to define a matching functional. Using this Hilbert space norm, we also derive and implement a surface matching algorithm under the large deformation framework, guaranteeing that the optimal solution is a one-to-one regular map of the entire ambient space. We detail an implementation of this algorithm for triangular meshes and present results on 3D face and medical image data.

  4. Resurgence matches quantization

    NASA Astrophysics Data System (ADS)

    Couso-Santamaría, Ricardo; Mariño, Marcos; Schiappa, Ricardo

    2017-04-01

    The quest to find a nonperturbative formulation of topological string theory has recently seen two unrelated developments. On the one hand, via quantization of the mirror curve associated to a toric Calabi–Yau background, it has been possible to give a nonperturbative definition of the topological-string partition function. On the other hand, using techniques of resurgence and transseries, it has been possible to extend the string (asymptotic) perturbative expansion into a transseries involving nonperturbative instanton sectors. Within the specific example of the local {{{P}}2} toric Calabi–Yau threefold, the present work shows how the Borel–Padé–Écalle resummation of this resurgent transseries, alongside occurrence of Stokes phenomenon, matches the string-theoretic partition function obtained via quantization of the mirror curve. This match is highly non-trivial, given the unrelated nature of both nonperturbative frameworks, signaling at the existence of a consistent underlying structure.

  5. Broadband electrical impedance matching for piezoelectric ultrasound transducers.

    PubMed

    Huang, Haiying; Paramo, Daniel

    2011-12-01

    This paper presents a systematic method for designing broadband electrical impedance matching networks for piezoelectric ultrasound transducers. The design process involves three steps: 1) determine the equivalent circuit of the unmatched piezoelectric transducer based on its measured admittance; 2) design a set of impedance matching networks using a computerized Smith chart; and 3) establish the simulation model of the matched transducer to evaluate the gain and bandwidth of the impedance matching networks. The effectiveness of the presented approach is demonstrated through the design, implementation, and characterization of impedance matching networks for a broadband acoustic emission sensor. The impedance matching network improved the power of the acquired signal by 9 times.

  6. Scheme for achieving coherent perfect absorption by anisotropic metamaterials.

    PubMed

    Zhang, Xiujuan; Wu, Ying

    2017-03-06

    We propose a unified scheme to achieve coherent perfect absorption of electromagnetic waves by anisotropic metamaterials. The scheme describes the condition on perfect absorption and offers an inverse design route based on effective medium theory in conjunction with retrieval method to determine practical metamaterial absorbers. The scheme is scalable to frequencies and applicable to various incident angles. Numerical simulations show that perfect absorption is achieved in the designed absorbers over a wide range of incident angles, verifying the scheme. By integrating these absorbers, we further propose an absorber to absorb energy from two coherent point sources.

  7. Metamaterial perfect absorber based on artificial dielectric "atoms".

    PubMed

    Liu, Xiaoming; Bi, Ke; Li, Bo; Zhao, Qian; Zhou, Ji

    2016-09-05

    In this work, we numerically designed and then experimentally verified a metamaterial perfect absorber based on artificial dielectric "atoms". This metamaterial absorber is composed of dielectric ceramic material (SrTiO3) "atoms" embedded in a background matrix on a metal plate. The dielectric "atoms" couple strongly to the incident electric and magnetic fields at the Mie resonance mode, leading to the narrow perfect absorption band with simulated and experimental absorptivities of 99% and 98.5% at 8.96 GHz, respectively. The designed metamaterial perfect absorber is polarization insensitive and can operate in wide angle incidence.

  8. Nearly Perfect Fluidity in a High Temperature Superconductor

    DOE PAGES

    Rameau, J. D.; Reber, T. J.; Yang, H. -B.; ...

    2014-10-13

    Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature Tc.

  9. Perfect extinction in subwavelength dual metallic transmitting gratings.

    PubMed

    Estruch, Thomas; Jaeck, Julien; Pardo, Fabrice; Derelle, Sophie; Primot, Jérôme; Pelouard, Jean-Luc; Haidar, Riad

    2011-08-15

    We investigate the strong electromagnetic coupling that settles in dual metallic grating structures. This coupling is evidenced to lead to a perfect optical extinction in the transmission spectrum. The behavior of this perfect extinction that strongly depends on the longitudinal space and the lateral displacement between the two gratings can be explained by a simple model that describes the interference between a propagating mode and a couple of evanescent modes. The results show that the electromagnetic transmission of the structure can be tuned by controlling the position of this perfect transmission extinction and thus pave the way to new types of infrared tunable filters. © 2011 Optical Society of America

  10. Nearly Perfect Fluidity in a High Temperature Superconductor

    SciTech Connect

    Rameau, J. D.; Reber, T. J.; Yang, H. -B.; Akhanjee, S.; Gu, G. D.; Johnson, P. D.; Campbell, S.

    2014-10-13

    Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature Tc.

  11. Match injury rates in professional soccer vary with match result, match venue, and type of competition.

    PubMed

    Bengtsson, Håkan; Ekstrand, Jan; Waldén, Markus; Hägglund, Martin

    2013-07-01

    Player activities in soccer matches are influenced by the match result and match venue. It is not known whether injury rates are influenced by these factors. To investigate whether there are associations between injury rates and the match result, venue, and type of competition in male soccer. Cohort study; Level of evidence, 3. Twenty-six professional clubs from 10 countries were followed prospectively during 9 seasons (2001-2002 to 2009-2010). All matches, and injuries occurring in these matches, were registered by the team's medical staff. An injury was registered if it resulted in player absence from training or matches. Information about match result, venue, and type of competition for all reported matches was gathered by the authors from online databases. Injury rates in matches with varying match characteristics were compared by use of generalized estimating equations. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. A total of 2738 injuries during 6010 matches were registered. There were no associations between odds of 1 injury occurrence and match result or type of competition, whereas the odds were decreased in matches played away compared with home matches (OR, 0.89; 95% CI, 0.80-0.99). The odds of 2 or more injury occurrences in a match were increased in matches resulting in a draw (OR, 1.39; 95% CI, 1.15-1.69) or loss (OR, 1.66; 95% CI, 1.38-1.98) compared with matches won and were decreased in other cup matches compared with league matches (OR, 0.57; 95% CI, 0.39-0.84) and in matches played away compared with home matches (OR, 0.70; 95% CI, 0.60-0.82). Finally, injuries with more than 1 week's absence occurred more frequently in Champions League matches compared with league matches both for matches with 1 injury (OR, 1.26; 95% CI, 1.09-1.45) and matches with 2 or more injuries (OR, 1.57; 95% CI, 1.13-2.20). The odds of 2 or more injury occurrences in professional soccer were higher in matches resulting in a loss or a draw compared

  12. Meanings and Distribution of the Perfect in Present-Day American English Prose.

    ERIC Educational Resources Information Center

    Dubois, Betty Lou

    This paper explores the meanings and distribution of the perfect in contemporary American English prose, with reference to problems encountered in teaching English as a second language. The English perfect comprises forms traditionally called present perfect tense, past perfect tense, and perfects of the infinitive, gerund and present participle.…

  13. Implications of cloning for breed improvement strategies: are traditional methods of animal improvement obsolete?

    PubMed

    van Vleck, L D

    1999-01-01

    Can the optimum animal be defined? Will that definition change over time, by location, by market demand? First, assume what may be impossible, that the perfect animal can be defined or that only a limited number of definitions of "perfect" are needed. Then, can the "perfect" animal to match a definition be found? Suppose such an animal is found. Then the question to be answered before trying to clone as a method of genetic improvement becomes "Is the animal perfect because of phenotype or genotype?" In other words, the P = G + E problem exists, which requires traditional methods of genetic evaluation and testing to determine whether genotype (G) or random environmental (E) effects or a combination leads to the apparent perfection in the phenotype (P). For most traits, additive genetic variance accounts for 10 to 50% of total variance, a fraction denoted as heritability. With a simple model, the best prediction of genotypic value is to reduce the apparent phenotypic superiority by multiplying by heritability. Cloning the "perfect" animal also could capture optimum dominance and epistatic genetic effects that are otherwise difficult to select for. For some traits, maternal effects are important. In that case, clones as breeding animals must be "perfect" for both direct and maternal genotypes, or alternatively terminal and maternal clone lines would need to be developed. The use of clones to increase uniformity can be only partially successful. If heritability is 25%, then the standard deviation among clones would be 87% of that of uncloned animals. Only if heritability is 100% will clone mates have complete uniformity. Fixing the genotype could increase susceptibility to failure if environment changes or if the cloned genotype is susceptible to a new disease or if economic conditions change. Cloning, at best, is another tool for animal improvement that joins the list of previous biotechnological inventions, some of which have become cost-effective, such as artificial

  14. Constructivist-Based Asynchronous Tutorial to Improve Transfer between Math and Chemistry Domains: Design, Implementation, and Analysis of the Impact of ReMATCH on General Chemistry Course Performance and Confidence

    NASA Astrophysics Data System (ADS)

    Barker, M. Danielle

    2011-07-01

    The two-year implementation of ReMATCH, a web-based math and problem-solving tutorial, in a traditionally arranged general chemistry classroom at the University of Kansas examined the impact of a designed intervention to assist students with the transfer of their mathematical knowledge to a chemistry context where it could be readily used for quantitative problem solving. The ReMATCH intervention, designed on constructivist-based pedagogies, focused on illuminating the expert-processes of problem solving and transferring knowledge across domains to the novice chemistry. The two implementations of ReMATCH -- once as lab assignments and once lecture assignments -- resulted in very different student responses to the intervention. However, within both, the beneficial effects of sustained ReMATCH-use were visible. In 2006, students who attempted all of the ReMATCH homework assignments were predicted to earn ˜5% higher on their total exam points. The 2007 implementation of ReMATCH demonstrated that students who attempted all of the homework problems and visited at least half of the ReMATCH tutorial pages were predicted to earn ˜8.5% higher on their total exam points. Additionally, use of ReMATCH in 2006 also resulted in increased confidence (as measured by comfort-level) with some of the math-related chemistry topics covered in ReMATCH. In 2007, when only students who attempted all of the ReMATCH problems were considered, it became clear that individuals who were initially less confident in their math-related chemistry skills were more likely to view more of the ReMATCH tutorial pages. When students with lower initial comfort-levels on these topics viewed at least half of the ReMATCH tutorial pages, they were able to compensate for their initially lower levels of confidence and were equally comfortable with most of the math-related chemistry topics by the final survey. Student interactions with and perceptions of ReMATCH showed that student attitudes towards ReMATCH

  15. Infrared Perfect Ultra-narrow Band Absorber as Plasmonic Sensor

    NASA Astrophysics Data System (ADS)

    Wu, Dong; Liu, Yumin; Li, Ruifang; Chen, Lei; Ma, Rui; Liu, Chang; Ye, Han

    2016-11-01

    We propose and numerically investigate a novel perfect ultra-narrow band absorber based on a metal-dielectric-metal-dielectric-metal periodic structure working at near-infrared region, which consists of a dielectric layer sandwiched by a metallic nanobar array and a thin gold film over a dielectric layer supported by a metallic film. The absorption efficiency and ultra-narrow band of the absorber are about 98 % and 0.5 nm, respectively. The high absorption is contributed to localized surface plasmon resonance, which can be influenced by the structure parameters and the refractive index of dielectric layer. Importantly, the ultra-narrow band absorber shows an excellent sensing performance with a high sensitivity of 2400 nm/RIU and an ultra-high figure of merit of 4800. The FOM of refractive index sensor is significantly improved, compared with any previously reported plasmonic sensor. The influences of structure parameters on the sensing performance are also investigated, which will have a great guiding role to design high-performance refractive index sensors. The designed structure has huge potential in sensing application.

  16. High performance projectile seal development for non perfect railgun bores

    SciTech Connect

    Wolfe, T.R.; Vine, F.E. Le; Riedy, P.E.; Panlasigui, A.; Hawke, R.S.; Susoeff, A.R.

    1997-01-01

    The sealing of high pressure gas behind an accelerating projectile has been developed over centuries of use in conventional guns and cannons. The principal concern was propulsion efficiency and trajectory accuracy and repeatability. The development of guns for use as high pressure equation-of-state (EOS) research tools, increased the importance of better seals to prevent gas leakage from interfering with the experimental targets. The development of plasma driven railguns has further increased the need for higher quality seals to prevent gas and plasma blow-by. This paper summarizes more than a decade of effort to meet these increased requirements. In small bore railguns, the first improvement was prompted by the need to contain the propulsive plasma behind the projectile to avoid the initiation of current conducting paths in front of the projectile. The second major requirements arose from the development of a railgun to serve as an EOS tool where it was necessary to maintain an evacuated region in front of the projectile throughout the acceleration process. More recently, the techniques developed for the small bore guns have been applied to large bore railguns and electro-thermal chemical guns in order to maximize their propulsion efficiency. Furthermore, large bore railguns are often less rigid and less straight than conventional homogeneous material guns. Hence, techniques to maintain seals in non perfect, non homogeneous material launchers have been developed and are included in this paper.

  17. Perfection and the Bomb: Nuclear Weapons, Teleology, and Motives.

    ERIC Educational Resources Information Center

    Brummett, Barry

    1989-01-01

    Uses Kenneth Burke's theory of perfection to explore the vocabularies of nuclear weapons in United States public discourse and how "the Bomb" as a God term has gained imbalanced ascendancy in centers of power. (MS)

  18. New exact perfect fluid solutions of Einstein's equations. II

    NASA Astrophysics Data System (ADS)

    Uggla, Claes; Rosquist, Kjell

    1990-12-01

    A family of new spatially homogeneous Bianchi type VIh perfect fluid solutions of the Einstein equations is presented. The fluid flow is orthogonal to the spatially homogeneous hypersurfaces, and the pressure is proportional to the energy density.

  19. Dynamics of microparticles trapped in a perfect vortex beam.

    PubMed

    Chen, Mingzhou; Mazilu, Michael; Arita, Yoshihiko; Wright, Ewan M; Dholakia, Kishan

    2013-11-15

    We analyze microparticle dynamics within a "perfect" vortex beam. In contrast to other vortex fields, for any given integer value of the topological charge, a "perfect" vortex beam has the same annular intensity profile with fixed radius of peak intensity. For a given topological charge, the field possesses a well-defined orbital angular momentum density at each point in space, invariant with respect to azimuthal position. We experimentally create a perfect vortex and correct the field in situ, to trap and set in motion trapped microscopic particles. For a given topological charge, a single trapped particle exhibits the same local angular velocity moving in such a field independent of its azimuthal position. We also investigate particle dynamics in "perfect" vortex beams of fractional topological charge. This light field may be applied for novel studies in optical trapping of particles, atoms, and quantum gases.

  20. Senseless demolition in progress, showing destruction of perfectly decent and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Senseless demolition in progress, showing destruction of perfectly decent and recyclable mill building. Problem exacerbated by high value of scrap iron. - Phoenix Iron Company, Rolling Mill, North of French Creek, west of Fairview Avenue, Phoenixville, Chester County, PA

  1. Perfection and the Bomb: Nuclear Weapons, Teleology, and Motives.

    ERIC Educational Resources Information Center

    Brummett, Barry

    1989-01-01

    Uses Kenneth Burke's theory of perfection to explore the vocabularies of nuclear weapons in United States public discourse and how "the Bomb" as a God term has gained imbalanced ascendancy in centers of power. (MS)

  2. Perfect Actions ---From the Theoretical Background to Recent Developments ---

    NASA Astrophysics Data System (ADS)

    Hasenfratz, P.

    This lecture note starts with a pedagogical introduction to the theoretical background and properties of perfect actions and ends with a discussion on the recent developments concerning chiral symmetry.

  3. Y junctions in photonic crystal channel waveguides: high transmission and impedance matching.

    PubMed

    Boscolo, S; Midrio, M; Krauss, T F

    2002-06-15

    We investigate the efficiency of transmission through photonic crystal Y junctions and show the importance of matching mode symmetries. Furthermore, we show that by adding tuning holes to the input waveguide it is possible to achieve almost perfect impedance matching, leading ideally to unitary transmission through the junction. The model system is based on a triangular photonic lattice of holes in dielectrics to reflect experimental reality.

  4. Bilingual Education and Telecommunications: A Perfect Fit.

    ERIC Educational Resources Information Center

    Sayers, Dennis; Brown, Kristin

    1987-01-01

    Describes Project Orillas, a telecommunications network designed to improve the writing skills of bilingual and foreign language students studying English and Spanish in Mexico, Puerto Rico, and the United States. The electronic bulletin board system used for communication is explained and guidelines for joining the network are included. (LRW)

  5. Digital matched filter ASIC

    NASA Astrophysics Data System (ADS)

    Magill, D. T.; Edwards, G.

    The architecture of a digital matched filter (DMF) and the selected technology used is described. The characteristics of the DMF ASIC are summarized in tabular form. Three architectures are considered for the implementation of a DMF ASIC. First, there is the conventional trapped delay line architecture which requires a large adder tree. The second architecture is the systolic array DMF which consists of a number of identical stages cascaded together. The third architecture is the bank-of-correlators DMF, in which the reference code is recirculated around through the delay line. Since the objective is to maximize the length of the DMF, the tapped delay line architecture is selected. The tapped delay form is designed to support BPSK, QPSK, and OQPSK chip modulation. Matched filter lengths of up to 256 chips can be supported by cascading 4 ASICs. The DMF is designed as a gate array using an advanced double metal, 1.5 micron CMOS process. The regularity of FIR filter architecture allows the core of the device to be laid out very compactly, resulting in efficient usage of the gate array.

  6. Multinomial pattern matching revisited

    NASA Astrophysics Data System (ADS)

    Horvath, Matthew S.; Rigling, Brian D.

    2015-05-01

    Multinomial pattern matching (MPM) is an automatic target recognition algorithm developed for specifically radar data at Sandia National Laboratories. The algorithm is in a family of algorithms that first quantizes pixel value into Nq bins based on pixel amplitude before training and classification. This quantization step reduces the sensitivity of algorithm performance to absolute intensity variation in the data, typical of radar data where signatures exhibit high variation for even small changes in aspect angle. Our previous work has focused on performance analysis of peaky template matching, a special case of MPM where binary quantization is used (Nq = 2). Unfortunately references on these algorithms are generally difficult to locate and here we revisit the MPM algorithm and illustrate the underlying statistical model and decision rules for two algorithm interpretations: the 1-of-K vector form and the scalar. MPM can also be used as a detector and specific attention is given to algorithm tuning where "peak pixels" are chosen based on their underlying empirical probabilities according to a reward minimization strategy aimed at reducing false alarms in the detection scenario and false positives in a classification capacity. The algorithms are demonstrated using Monte Carlo simulations on the AFRL civilian vehicle dataset for variety of choices of Nq.

  7. Perfecting patient flow in the surgical setting.

    PubMed

    Amato-Vealey, Elaine J; Fountain, Patricia; Coppola, Deborah

    2012-07-01

    Reduced surgical efficiency and productivity, delayed patient discharges, and prolonged use of hospital resources are the results of an OR that is unable to move patients to the postanesthesia care unit or other patient units. A primary reason for perioperative patient flow delay is the lack of hospital beds to accommodate surgical patients, which consequently causes backups of patients currently in the surgical suite. In one facility, implementing Six Sigma methodology helped to improve OR patient flow by identifying ways that frontline staff members could work more intelligently and more efficiently, and with less stress to streamline workflow and eliminate redundancy and waste in ways that did not necessitate reducing the number of employees. The results were improved employee morale, job satisfaction and safety, and an enhanced patient experience.

  8. Regularity and Matching Pursuit feature extraction for the detection of epileptic seizures.

    PubMed

    Z-Flores, Emigdio; Trujillo, Leonardo; Sotelo, Arturo; Legrand, Pierrick; Coria, Luis N

    2016-06-15

    The neurological disorder known as epilepsy is characterized by involuntary recurrent seizures that diminish a patient's quality of life. Automatic seizure detection can help improve a patient's interaction with her/his environment, and while many approaches have been proposed the problem is still not trivially solved. In this work, we present a novel methodology for feature extraction on EEG signals that allows us to perform a highly accurate classification of epileptic states. Specifically, Hölderian regularity and the Matching Pursuit algorithm are used as the main feature extraction techniques, and are combined with basic statistical features to construct the final feature sets. These sets are then delivered to a Random Forests classification algorithm to differentiate between epileptic and non-epileptic readings. Several versions of the basic problem are tested and statistically validated producing perfect accuracy in most problems and 97.6% accuracy on the most difficult case. A comparison with recent literature, using a well known database, reveals that our proposal achieves state-of-the-art performance. The experimental results show that epileptic states can be accurately detected by combining features extracted through regularity analysis, the Matching Pursuit algorithm and simple time-domain statistical analysis. Therefore, the proposed method should be considered as a promising approach for automatic EEG analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. The earliest matches.

    PubMed

    Goren-Inbar, Naama; Freikman, Michael; Garfinkel, Yosef; Goring-Morris, A Nigel; Goring-Morris, Nigel A; Grosman, Leore

    2012-01-01

    Cylindrical objects made usually of fired clay but sometimes of stone were found at the Yarmukian Pottery Neolithic sites of Sha'ar HaGolan and Munhata (first half of the 8(th) millennium BP) in the Jordan Valley. Similar objects have been reported from other Near Eastern Pottery Neolithic sites. Most scholars have interpreted them as cultic objects in the shape of phalli, while others have referred to them in more general terms as "clay pestles," "clay rods," and "cylindrical clay objects." Re-examination of these artifacts leads us to present a new interpretation of their function and to suggest a reconstruction of their technology and mode of use. We suggest that these objects were components of fire drills and consider them the earliest evidence of a complex technology of fire ignition, which incorporates the cylindrical objects in the role of matches.

  10. The Earliest Matches

    PubMed Central

    Goren-Inbar, Naama; Freikman, Michael; Garfinkel, Yosef; Goring-Morris, Nigel A.; Grosman, Leore

    2012-01-01

    Cylindrical objects made usually of fired clay but sometimes of stone were found at the Yarmukian Pottery Neolithic sites of Sha‘ar HaGolan and Munhata (first half of the 8th millennium BP) in the Jordan Valley. Similar objects have been reported from other Near Eastern Pottery Neolithic sites. Most scholars have interpreted them as cultic objects in the shape of phalli, while others have referred to them in more general terms as “clay pestles,” “clay rods,” and “cylindrical clay objects.” Re-examination of these artifacts leads us to present a new interpretation of their function and to suggest a reconstruction of their technology and mode of use. We suggest that these objects were components of fire drills and consider them the earliest evidence of a complex technology of fire ignition, which incorporates the cylindrical objects in the role of matches. PMID:22870306

  11. Matching pursuit parallel decomposition of seismic data

    NASA Astrophysics Data System (ADS)

    Li, Chuanhui; Zhang, Fanchang

    2017-07-01

    In order to improve the computation speed of matching pursuit decomposition of seismic data, a matching pursuit parallel algorithm is designed in this paper. We pick a fixed number of envelope peaks from the current signal in every iteration according to the number of compute nodes and assign them to the compute nodes on average to search the optimal Morlet wavelets in parallel. With the help of parallel computer systems and Message Passing Interface, the parallel algorithm gives full play to the advantages of parallel computing to significantly improve the computation speed of the matching pursuit decomposition and also has good expandability. Besides, searching only one optimal Morlet wavelet by every compute node in every iteration is the most efficient implementation.

  12. Distinctiveness Maps for Image Matching

    NASA Technical Reports Server (NTRS)

    Manduchi, Roberto; Tomasi, Carlo

    2000-01-01

    Stereo correspondence is hard because different image features can look alike. We propose a measure for the ambiguity of image points that allows matching distinctive points first and breaks down the matching task into smaller and separate subproblems. Experiments with an algorithm based on this measure demonstrate the ensuing efficiency and low likelihood of incorrect matches.

  13. Structural color printing based on plasmonic metasurfaces of perfect light absorption.

    PubMed

    Cheng, Fei; Gao, Jie; Luk, Ting S; Yang, Xiaodong

    2015-06-05

    Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.

  14. Structural color printing based on plasmonic metasurfaces of perfect light absorption

    SciTech Connect

    Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong

    2015-06-05

    Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.

  15. Structural color printing based on plasmonic metasurfaces of perfect light absorption

    PubMed Central

    Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong

    2015-01-01

    Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage. PMID:26047486

  16. Structural color printing based on plasmonic metasurfaces of perfect light absorption

    NASA Astrophysics Data System (ADS)

    Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong

    2015-06-01

    Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.

  17. Synthesis of CoFe/Al2O3 composite nanoparticles as the impedance matching layer of wideband multilayer absorber

    NASA Astrophysics Data System (ADS)

    Zhen, L.; Gong, Y. X.; Jiang, J. T.; Xu, C. Y.; Shao, W. Z.; Liu, P.; Tang, J.

    2011-04-01

    CoFe/Al2O3 composite nanoparticles were successfully prepared by hydrogen-thermally reducing cobalt aluminum ferrite. Compared with CoFe alloy nanoparticles, the permeability of CoFe/Al2O3 composite nanoparticles was remarkably enhanced and an improved impedance characteristic was achieved due to the introduction of insulated Al2O3. A multilayer absorber with CoFe/Al2O3 composite nanoparticles as the impedance matching layer and CoFe nanoflake as the dissipation layer was designed by using genetic algorithm, in which an ultrawide operation frequency bandwidth over 2.5-18 GHz was obtained. The microwave absorption performance in both normal and oblique incident case was evaluated by using electromagnetic simulator. The backward radar cross-section (RCS) was decreased at least 10 dB over a wide frequency range by covering the multilayer absorber on the surface of perfect electrical conductive plate.

  18. Feature matching evaluation for multimodal correspondence

    NASA Astrophysics Data System (ADS)

    Gesto-Diaz, M.; Tombari, F.; Gonzalez-Aguilera, D.; Lopez-Fernandez, L.; Rodriguez-Gonzalvez, P.

    2017-07-01

    This paper proposes a study and evaluation of approaches aimed at image matching under different modalities, together with a survey of methodologies used for performance comparison in this specific context, and, finally, a novel algorithm for image matching. First, a new dataset is introduced to overcome the limitations of existing datasets, which includes modalities such as visible, thermal, intensity and depth images. This dataset is used to compare the state of the art of feature detectors and descriptors. Template matching techniques commonly used to carry out multimodal correspondence are also adapted and compared therein. In total, 28 different combinations of detectors and descriptors are evaluated. In addition, the detectors' repeatability and the assessment of matching results based on Receiving Operating Characteristic (ROC) curve associated to all tested detector-descriptor combinations are presented, highlighting the best performing pairs. Finally, a novel Adaptive Pairwise Matching (APM) algorithm created to improve the robustness of matching towards outliers is also proposed and tested within our evaluation framework.

  19. Biomechanics and biocompatibility of the perfect conduit—can we build one?

    PubMed Central

    Ng, Martin K.C.; Bannon, Paul G.

    2013-01-01

    No currently available conduit meets the criteria for an ideal coronary artery bypass graft. The perfect conduit would combine the availability and complication-free harvest of a synthetic vessel with the long-term patency performance of the internal mammary artery. However, current polymer conduits suffer from inelastic mechanical properties and especially poor surface biocompatibility, resulting in early loss of patency as a coronary graft. Approaches to manufacture an improved conduit using new polymers or polymer surfaces, acellular matrices, or cellular constructs have to date failed to achieve a commercially successful alternative. Elastin, by mimicking the native extracellular environment as well as providing elasticity, provides the ‘missing link’ in vascular conduit design and brings new hope for realization of the perfect conduit. PMID:23977620

  20. Class of near-perfect coded apertures

    NASA Technical Reports Server (NTRS)

    Cannon, T. M.; Fenimore, E. E.

    1977-01-01

    Coded aperture imaging of gamma ray sources has long promised an improvement in the sensitivity of various detector systems. The promise has remained largely unfulfilled, however, for either one of two reasons. First, the encoding/decoding method produces artifacts, which even in the absence of quantum noise, restrict the quality of the reconstructed image. This is true of most correlation-type methods. Second, if the decoding procedure is of the deconvolution variety, small terms in the transfer function of the aperture can lead to excessive noise in the reconstructed image. It is proposed to circumvent both of these problems by use of a uniformly redundant array (URA) as the coded aperture in conjunction with a special correlation decoding method.

  1. Practice makes perfect in memory recall.

    PubMed

    Romani, Sandro; Katkov, Mikhail; Tsodyks, Misha

    2016-04-01

    A large variability in performance is observed when participants recall briefly presented lists of words. The sources of such variability are not known. Our analysis of a large data set of free recall revealed a small fraction of participants that reached an extremely high performance, including many trials with the recall of complete lists. Moreover, some of them developed a number of consistent input-position-dependent recall strategies, in particular recalling words consecutively ("chaining") or in groups of consecutively presented words ("chunking"). The time course of acquisition and particular choice of positional grouping were variable among participants. Our results show that acquiring positional strategies plays a crucial role in improvement of recall performance. © 2016 Romani et al.; Published by Cold Spring Harbor Laboratory Press.

  2. Interference control of perfect photon absorption in cavity quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Wang, Liyong; Di, Ke; Zhu, Yifu; Agarwal, G. S.

    2017-01-01

    We propose and analyze a scheme for controlling coherent photon transmission and reflection in a cavity-quantum-electrodynamics (CQED) system consisting of an optical resonator coupled with three-level atoms coherently prepared by a control laser from free space. When the control laser is off and the cavity is excited by two identical light fields from two ends of the cavity, the two input light fields can be completely absorbed by the CQED system and the light energy is converted into the excitation of the polariton states, but no light can escape from the cavity. Two distinct cases of controlling the perfect photon absorption are analyzed: (a) when the control laser is tuned to the atomic resonance and creates electromagnetically induced transparency, the perfect photon absorption is suppressed and the input light fields are nearly completely transmitted through the cavity; (b) when the control laser is tuned to the polariton state resonance and inhibits the polariton state excitation, the perfect photon absorption is again suppressed and the input light fields are nearly completely reflected from the cavity. Thus, the CQED system can act as a perfect absorber or near-perfect transmitter and/or reflector by simply turning the control laser off or on. Such interference control of the coherent photon-atom interaction in the CQED system should be useful for a variety of applications in optical logical devices.

  3. Almost perfect sequences applied for ionospheric oblique backscattering detection

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Zhao, Zhengyu; Pu, Tianyao; Huang, Yujie; Zhu, Guoqiang

    2009-10-01

    Pseudorandom sequences are often used in radio systems; however, the nonzero out-of-phase autocorrelation of many binary sequences induces range sidelobes which significantly reduce the echo signal-to-noise ratio (SNR). In this paper, the use of almost perfect sequences, exhibiting zero out-of-phase autocorrelation except one value in the middle is examined with reference to common m sequences and perfect sequence. The ambiguity functions demonstrate that it is possible to use the almost perfect sequences for ranging without sidelobes and that their Doppler measurement performance is similar to m sequence of the same length. This is an important result for ionospheric oblique backscattering detection where the echoes are superposed and where range sidelobes can submerge the main lobes of weak signals. The 124-bit almost perfect sequence and the 127-bit m sequence are applied to the Wuhan Ionospheric Oblique Backscattering Sounding System for sequence testing. The test results have proven that the almost perfect sequence exhibits a higher echo SNR for the same detection conditions.

  4. Refractive surgery: the future of perfect vision?

    PubMed

    Fong, C S

    2007-08-01

    The history of refractive eye surgery is recent, but has seen rapid advancement. Older technologies, such as radial keratectomy, had the problem of overcorrection and epithelial complications. Newer technologies, such as photorefractive keratectomy, laser-assisted in-situ keratomileusis (LASIK) and laser-assisted subepithelial keratomileusis (LASEK), which require the use of laser, has revolutionised eye surgery. However, there are complications, such as corneal hazing, postoperative pain, regression, and poorer correction for high myopes. If not contraindicated, wavefront analysis and femtosecond laser are useful adjuncts to laser photoablation for better visual results. Wavefront analysis improves the precision of laser photoablation by measuring the individual's wavefront aberrations, while femtosecond laser offers an instrument-free means of creating the corneal hinge. Lastly, implantation of intraocular lenses, with or without extraction of the crystalline lens, provides an alternative to laser photoablation for the treatment of high myopia. Clear lens exchange offers refractive correction to presbyopes and people with cataracts. However, complications, such as endothelial cell loss, cataract formation and retinal detachment, exist. In conclusion, refractive eye surgery provides an alternative to wearing spectacles or contact lenses. However, potential patients must be warned of the complications and long-term effects on the eyes.

  5. Large-Scale All-Dielectric Metamaterial Perfect Reflectors

    DOE PAGES

    Moitra, Parikshit; Slovick, Brian A.; li, Wei; ...

    2015-05-08

    All-dielectric metamaterials offer a potential low-loss alternative to plasmonic metamaterials at optical frequencies. In this paper, we take advantage of the low absorption loss as well as the simple unit cell geometry to demonstrate large-scale (centimeter-sized) all-dielectric metamaterial perfect reflectors made from silicon cylinder resonators. These perfect reflectors, operating in the telecommunications band, were fabricated using self-assembly based nanosphere lithography. In spite of the disorder originating from the self-assembly process, the average reflectance of the metamaterial perfect reflectors is 99.7% at 1530 nm, surpassing the reflectance of metallic mirrors. Moreover, the spectral separation of the electric and magnetic resonances canmore » be chosen to achieve the required reflection bandwidth while maintaining a high tolerance to disorder. Finally, the scalability of this design could lead to new avenues of manipulating light for low-loss and large-area photonic applications.« less

  6. Experimental perfect state transfer of an entangled photonic qubit.

    PubMed

    Chapman, Robert J; Santandrea, Matteo; Huang, Zixin; Corrielli, Giacomo; Crespi, Andrea; Yung, Man-Hong; Osellame, Roberto; Peruzzo, Alberto

    2016-04-18

    The transfer of data is a fundamental task in information systems. Microprocessors contain dedicated data buses that transmit bits across different locations and implement sophisticated routing protocols. Transferring quantum information with high fidelity is a challenging task, due to the intrinsic fragility of quantum states. Here we report on the implementation of the perfect state transfer protocol applied to a photonic qubit entangled with another qubit at a different location. On a single device we perform three routing procedures on entangled states, preserving the encoded quantum state with an average fidelity of 97.1%, measuring in the coincidence basis. Our protocol extends the regular perfect state transfer by maintaining quantum information encoded in the polarization state of the photonic qubit. Our results demonstrate the key principle of perfect state transfer, opening a route towards data transfer for quantum computing systems.

  7. Large-Scale All-Dielectric Metamaterial Perfect Reflectors

    SciTech Connect

    Moitra, Parikshit; Slovick, Brian A.; li, Wei; Kravchencko, Ivan I.; Briggs, Dayrl P.; Krishnamurthy, S.; Valentine, Jason

    2015-05-08

    All-dielectric metamaterials offer a potential low-loss alternative to plasmonic metamaterials at optical frequencies. In this paper, we take advantage of the low absorption loss as well as the simple unit cell geometry to demonstrate large-scale (centimeter-sized) all-dielectric metamaterial perfect reflectors made from silicon cylinder resonators. These perfect reflectors, operating in the telecommunications band, were fabricated using self-assembly based nanosphere lithography. In spite of the disorder originating from the self-assembly process, the average reflectance of the metamaterial perfect reflectors is 99.7% at 1530 nm, surpassing the reflectance of metallic mirrors. Moreover, the spectral separation of the electric and magnetic resonances can be chosen to achieve the required reflection bandwidth while maintaining a high tolerance to disorder. Finally, the scalability of this design could lead to new avenues of manipulating light for low-loss and large-area photonic applications.

  8. Numerical study of perfect wetting in quenched QCD

    NASA Astrophysics Data System (ADS)

    Brower, R.; Huang, S.; Potvin, J.; Rebbi, C.; Ross, J.

    1992-11-01

    In the quenched approximation of QCD, the high-temperature phase (or gluon plasma phase) will be found in one of three degenerate vacua characterized by the average value of the Polyakov loop. Such vacua can coexist separated by a sharp interface. As T-->T+c (the confinement temperature) confined or glueball matter may be able to grow as a layer along this interface. QCD is said to obey perfect wetting if these layers are planar, or imperfect wetting if they are shaped like lenses. Evidence for perfect wetting in quenched QCD is studied from a calculation of the surface tension αp,p/T3 between two high-temperature plasma phases at Tc on a 162×32×4 lattice. By comparison with the value of the surface tension of a hadron-plasma interface, the data suggest that planar slabs or at least very long lenses develop along the interface, implying that QCD obeys perfect wetting.

  9. Experimental perfect state transfer of an entangled photonic qubit

    PubMed Central

    Chapman, Robert J.; Santandrea, Matteo; Huang, Zixin; Corrielli, Giacomo; Crespi, Andrea; Yung, Man-Hong; Osellame, Roberto; Peruzzo, Alberto

    2016-01-01

    The transfer of data is a fundamental task in information systems. Microprocessors contain dedicated data buses that transmit bits across different locations and implement sophisticated routing protocols. Transferring quantum information with high fidelity is a challenging task, due to the intrinsic fragility of quantum states. Here we report on the implementation of the perfect state transfer protocol applied to a photonic qubit entangled with another qubit at a different location. On a single device we perform three routing procedures on entangled states, preserving the encoded quantum state with an average fidelity of 97.1%, measuring in the coincidence basis. Our protocol extends the regular perfect state transfer by maintaining quantum information encoded in the polarization state of the photonic qubit. Our results demonstrate the key principle of perfect state transfer, opening a route towards data transfer for quantum computing systems. PMID:27088483

  10. Constraint-based stereo matching

    NASA Technical Reports Server (NTRS)

    Kuan, D. T.

    1987-01-01

    The major difficulty in stereo vision is the correspondence problem that requires matching features in two stereo images. Researchers describe a constraint-based stereo matching technique using local geometric constraints among edge segments to limit the search space and to resolve matching ambiguity. Edge segments are used as image features for stereo matching. Epipolar constraint and individual edge properties are used to determine possible initial matches between edge segments in a stereo image pair. Local edge geometric attributes such as continuity, junction structure, and edge neighborhood relations are used as constraints to guide the stereo matching process. The result is a locally consistent set of edge segment correspondences between stereo images. These locally consistent matches are used to generate higher-level hypotheses on extended edge segments and junctions to form more global contexts to achieve global consistency.

  11. An HLA matched donor! An HLA matched donor? What do you mean by: HLA matched donor?

    PubMed

    van Rood, J J; Oudshoorn, M

    1998-07-01

    The term 'an HLA matched donor' is in general used without giving exact information on the level of resolution of the HLA typing. This can lead to misunderstandings. A proposal is formulated to agree on using six match categories according to the HLA typing technique used to indicate the level of confidence of the matching.

  12. Global Patch Matching

    NASA Astrophysics Data System (ADS)

    Huang, X.; Hu, K.; Ling, X.; Zhang, Y.; Lu, Z.; Zhou, G.

    2017-09-01

    This paper introduces a novel global patch matching method that focuses on how to remove fronto-parallel bias and obtain continuous smooth surfaces with assuming that the scenes covered by stereos are piecewise continuous. Firstly, simple linear iterative cluster method (SLIC) is used to segment the base image into a series of patches. Then, a global energy function, which consists of a data term and a smoothness term, is built on the patches. The data term is the second-order Taylor expansion of correlation coefficients, and the smoothness term is built by combing connectivity constraints and the coplanarity constraints are combined to construct the smoothness term. Finally, the global energy function can be built by combining the data term and the smoothness term. We rewrite the global energy function in a quadratic matrix function, and use least square methods to obtain the optimal solution. Experiments on Adirondack stereo and Motorcycle stereo of Middlebury benchmark show that the proposed method can remove fronto-parallel bias effectively, and produce continuous smooth surfaces.

  13. Tunable graphene-based mid-infrared plasmonic wide-angle narrowband perfect absorber.

    PubMed

    Li, Hongju; Wang, Lingling; Zhai, Xiang

    2016-11-15

    In this paper, the periodic double-layer graphene ribbon arrays placed near a metallic ground plate coated by a dielectric layer are proposed and analyzed by the coupled-mode theory (CMT) to predict the perfect absorption response in the mid-infrared region. Numerical simulations of the finite-difference time-domain (FDTD) method confirm this effect and give the underlying physical origin. The anti-symmetric dipole-dipole coupling mode is supported by the double-layer graphene ribbons and acts as the electrical resonance to suppress the reflection, because of the impedance matching. The transmission from this system is restricted by the ultra-thick metallic ground plate. All incident electromagnetic energy is efficiently confined in the interlayer between graphene ribbons and the metallic plate, and the dramatic narrowband perfect absorption peak with the FWHM (full width at half maximums) of 300 nm hence is achieved. The spectral position of the absorption peak can be dynamically tuned by a small change in the chemical potential of graphene, in addition to varying geometrical parameters of the absorber. Meanwhile, this device exhibits good absorption stability over a wide angle range of incidence around ± 60° at least. Such absorber will benefit the fabrication of mid-infrared nano-photonic devices for optical filtering and storage.

  14. Tunable graphene-based mid-infrared plasmonic wide-angle narrowband perfect absorber

    PubMed Central

    Li, Hongju; Wang, Lingling; Zhai, Xiang

    2016-01-01

    In this paper, the periodic double-layer graphene ribbon arrays placed near a metallic ground plate coated by a dielectric layer are proposed and analyzed by the coupled-mode theory (CMT) to predict the perfect absorption response in the mid-infrared region. Numerical simulations of the finite-difference time-domain (FDTD) method confirm this effect and give the underlying physical origin. The anti-symmetric dipole-dipole coupling mode is supported by the double-layer graphene ribbons and acts as the electrical resonance to suppress the reflection, because of the impedance matching. The transmission from this system is restricted by the ultra-thick metallic ground plate. All incident electromagnetic energy is efficiently confined in the interlayer between graphene ribbons and the metallic plate, and the dramatic narrowband perfect absorption peak with the FWHM (full width at half maximums) of 300 nm hence is achieved. The spectral position of the absorption peak can be dynamically tuned by a small change in the chemical potential of graphene, in addition to varying geometrical parameters of the absorber. Meanwhile, this device exhibits good absorption stability over a wide angle range of incidence around ± 60° at least. Such absorber will benefit the fabrication of mid-infrared nano-photonic devices for optical filtering and storage. PMID:27845350

  15. Tunable graphene-based mid-infrared plasmonic wide-angle narrowband perfect absorber

    NASA Astrophysics Data System (ADS)

    Li, Hongju; Wang, Lingling; Zhai, Xiang

    2016-11-01

    In this paper, the periodic double-layer graphene ribbon arrays placed near a metallic ground plate coated by a dielectric layer are proposed and analyzed by the coupled-mode theory (CMT) to predict the perfect absorption response in the mid-infrared region. Numerical simulations of the finite-difference time-domain (FDTD) method confirm this effect and give the underlying physical origin. The anti-symmetric dipole-dipole coupling mode is supported by the double-layer graphene ribbons and acts as the electrical resonance to suppress the reflection, because of the impedance matching. The transmission from this system is restricted by the ultra-thick metallic ground plate. All incident electromagnetic energy is efficiently confined in the interlayer between graphene ribbons and the metallic plate, and the dramatic narrowband perfect absorption peak with the FWHM (full width at half maximums) of 300 nm hence is achieved. The spectral position of the absorption peak can be dynamically tuned by a small change in the chemical potential of graphene, in addition to varying geometrical parameters of the absorber. Meanwhile, this device exhibits good absorption stability over a wide angle range of incidence around ± 60° at least. Such absorber will benefit the fabrication of mid-infrared nano-photonic devices for optical filtering and storage.

  16. Dual band metamaterial perfect absorber based on artificial dielectric "molecules".

    PubMed

    Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhao, Qian; Zhou, Ji

    2016-07-13

    Dual band metamaterial perfect absorbers with two absorption bands are highly desirable because of their potential application areas such as detectors, transceiver system, and spectroscopic imagers. However, most of these dual band metamaterial absorbers proposed were based on resonances of metal patterns. Here, we numerically and experimentally demonstrate a dual band metamaterial perfect absorber composed of artificial dielectric "molecules" with high symmetry. The artificial dielectric "molecule" consists of four "atoms" of two different sizes corresponding to two absorption bands with near unity absorptivity. Numerical and experimental absorptivity verify that the dual-band metamaterial absorber is polarization insensitive and can operate in wide-angle incidence.

  17. Dual band metamaterial perfect absorber based on Mie resonances

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoming; Lan, Chuwen; Bi, Ke; Li, Bo; Zhao, Qian; Zhou, Ji

    2016-08-01

    We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric "atom" with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric "atom" and copper plate. Mie resonances of dielectric "atom" provide a simple way to design metamaterial perfect absorbers with high symmetry.

  18. Computational issues for perfect simulation in spatial point patterns

    NASA Astrophysics Data System (ADS)

    Mateu, Jorge; Artés, Jordi; López, José A.

    2004-04-01

    Due to model complexity, spatial statistics often relies on simulation methods. Probably the most common such method is Markov chain Monte Carlo (MCMC) which draws approximate samples of the target distribution as the equilibrium distribution of a Markov chain. Perfect simulation methods are MCMC algorithms which ensure that the exact target distribution is sampled. This paper describes perfect simulation methods of locally stable point processes based on coupling from the past algorithms and provides an intensive simulation study analyzing the behaviour of these techniques under a large variety of practical situations.

  19. Dual band metamaterial perfect absorber based on Mie resonances

    SciTech Connect

    Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhou, Ji; Bi, Ke; Zhao, Qian

    2016-08-08

    We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric “atom” with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric “atom” and copper plate. Mie resonances of dielectric “atom” provide a simple way to design metamaterial perfect absorbers with high symmetry.

  20. Clebsch Potentials in the Variational Principle for a Perfect Fluid

    NASA Astrophysics Data System (ADS)

    Fukagawa, H.; Fujitani, Y.

    2010-09-01

    Equations for a perfect fluid can be obtained by means of the variational principle both in the Lagrangian description and in the Eulerian one. It is known that we need additional fields somehow to describe a rotational isentropic flow in the latter description. We give a simple explanation for these fields; they are introduced to fix both ends of a pathline in the variational calculus. This restriction is imposed in the former description, and should be imposed in the latter description. It is also shown that we can derive a canonical Hamiltonian formulation for a perfect fluid by regarding the velocity field as the input in the framework of control theory.